Ver1.5.3

NetHelper release 1.5.3

Do not mix versions of NetHelper between different copies of Outpost 2 when playing multiplayer!

Changelog:

• Updated to newer versions of libnatpmp and miniupnp.
  • Cuts down cleanup/destruction on application closing from 3 mins to 8 secs.
• Changed dependency references from precompiled library files to Git submodules.
• Removed dependencies on msvcr100.dll and msvcp100.dll by statically compiling.
• Set release compilation optimization properties closer to MSVC default settings.
• Removed deprecated POSIX networking functions.
• Update code to remove benign variable type conversion warning in Patcher.