add travis build

only build
Added hack to fsproj files to build from the command line.  See https://github.com/dungpa/fantomas/issues/104 for details.
(This isn't worth merging - there's a real fix in progress, but it depends on other Xamarin Studio changes happening first)
add nuget
run tests
add build status badge
Merge pull request #122 from enricosada/travis_build

add travis ci build