- msvc does not support autotools &
  hunspell's build scripts itself do not play well with msvc
- just compile the hunspell-1.7.lib with cc "by hand"
- keep build without msvc as it is

- build-autotools to build with autotools
- build-cc to build with cc
- default is build-autotools
- added documentation into Readme.md to show
  how to enable build-cc

- added information about target specific

- by default hunspell is searched by pkg-config
- optionally - with feature bundled - hunspell is build from
  directory vendor by crate cc
- documented this in README.md
- extended .travis.yml to test building the bundled hunspell

- for testing feature bundled

- for testing all features in all rust versions