Release v-0.20.0-incubating-candidate-1

• Docker Ubuntu tweaks (#2975)
• update license information (#2977)
• [healthmgr] fix style (#2983)
• fixsimportimport (#2982)
• [healthmgr] refactor physicalplanprovider and topologyprovider (#2979)
• Adding average Serialization/Deserialization time per tuple (#2976)
• Update error message in RuntimeManagerMain when an exception is catched (#2974)
• Fixed Spelling. (#2971)
• package c++ .h and .a files (#2961)
• spill state to local disk when configured (#2967)
• fix metrics name (#2970)
• fixing download issue in Nomad scheduler (#2969)
• Upgrade to the latest Dhalion (#2968)
• (Ok To Merge) updating docker scripts (#2963)
• Fix supervisor installation in Centos 7 Dockerfile (#2966)
• add integration test for instance state in stateful processing (#2956)
• joshfischer/update k8s docs (#2960)
• Counting pending tuples (#2951)
• Make checkpoint manager's ram configurable (#2958)
• Added endpoint to tracker to fetch packing plan. (#2959)
• [aurora] add metadata support for aurora (#2934)
• Refactor StatefulStorage API (#2891)
• Add log in Bolt/Spout instances after persisting state (#2954)
• Nwang/fix negative index caused by hash mod (#2953)
• Counting pending tuples (#2945)
• Revert the latest version number change of scala rules (#2943)
• [healthmgr] Enable runtime toggle for AutoRestartBackpressureContainerPolicy (#2923)
• Universal heronpy (#2948)
• added S3 uploader configuration in Helm chart (#2939)
• modify travis ci to enable integration topology test (#2940)
• add tmaster physical plan endpoint (#2941)
• add integration topology test (#2938)
• Add component config in heron UI and Tracker (#2860)
• Make TopologyBuilder less permissive (#2929)
• Clean up website gen + website python docs (#2928)
• make EvitionContext extend Serializable (#2935)
• Clean up remaining dead references to Twitter (#2930)
• Upgrade to Bazel 0.14.1 (#2932)
• Fix code when submitting a toplogy file without an known extension (#2933)
• Update governance.md and clean up Twitter related content (#2926)
• Add JDK/JAVA_HOME to bazel_configure.py (#2921)
• Fix integer types to avoid warnings (#2922)
• Correct case of acronyms (#2920)
• Add permissive licence to libunwind (#2914)
• Add DISCLAIMER file required by Apache policy (#2916)
• make LocalFSStorage clean checkpoints before store (#2910)
• refactor healthmgr build (#2912)
• refactor downlaoder build (#2911)
• reorder (#2908)
• log the object when it cannot be serialized when emitting tuples (#2905)
• Making emit, ack, and fail thread safe (#2692)
• add .htaccess and index.html [https://github.com//issues/2758] (#2872)
• Make MetricsManager.java a target so that it can be customized (#2902)
• cleaning removed directory (#2903)
• Refactor CheckpointManager to move initialization code out of constructor (#2901)
• Add extra info when failed to create new instance of class (#2870)
• add documentation about nomad consul integration (#2898)
• add src export (#2899)
• submit topology file by uri (#2886)
• move downloader registry map to yaml (#2884)
• Nwang/update license in other files (#2895)
• fixing test (#2894)
• Refactoring Nomad documentation and add documentation on running heron via docker on Nomad (#2876)
• Update license text in py files (#2889)
• pull yaml cpp for official release page (#2893)
• check checkpoint file exists before deleting it (#2883)
• remove thrift and scribe to prepare for apache release (#2879)
• Update license text in yaml files (#2887)
• Update license text in scala files (#2888)
• Update license text in H files (#2885)
• Update license text in java files (#2881)
• Update license text in cpp files (#2882)
• Update NOTICE file (#2878)
• Scala Streamlet API Documentation is being added (#2871)
• add .htaccess and index.html [https://github.com//issues/2758] (#2869)
• Fix kryo factor config (#2868)
• Add extra info when failed to create new instance of class (#2867)
• improving nomad launch script (#2862)
• k8s ensure response body is closed after reading an error. (#2863)
• [Streamlet Scala API] Add Scala Streamlet Integration Tests Part II (#2861)
• fix healthmgr metrics (#2839)
• Integrate runtime config and rate limit (#2846)
• package rename and related fixes (#2853)
• Align MetricsCacheMgr location discovery in Stmgr (#2797)
• Update Dhalion dependency version (#2821)
• [Streamlet Scala API] Add Scala Streamlet Integration Tests Part I (#2826)
• Rate limit needs to be disabled before the bufferevent_free call (#2848)
• Add sha256 checksums for all http_archives (#2856)
• expose heron metrics as a service in Nomad (#2859)
• Add two backup urls for zookeeper (#2857)
• Joshfischer/eco stateful topology (#2851)
• Eco for heron topologies (#2849)
• Add json format for dry-run (#2842)
• add config for apiserver overrides (#2845)
• While emitting in spout, adhere to the batch size limit (#2798)
• avoid make install for libunwind (#2844)
• Heron JavaDoc and Documentation Fixes (#2838)
• removed glog/gperftools/libevent/libunwind/zookeeper tar.gz from source (#2833)