Added basic c# support. Fixes travis-ci/travis-ci#649
support for the D Programming Language

- all 3 compilers supported dmd, ldc, gdc (each with different versions)

- no sudo required, only fetch, unpack and add to PATH
Julia support
Merge pull request #318 from ninjin/julia

Julia support
Merge pull request #340 from MartinNowak/dlang

support for the D Programming Language
Merge pull request #294 from Joshua-Anderson/csharp

Added basic C# support

Conflicts:
	lib/travis/build/script.rb
Merge pull request #318 from ninjin/julia

Julia support

Conflicts:
	lib/travis/build/script/julia.rb
Julia support
Extract and set package name as `JL_PKG`
Make package name regexp conform with Julia base
Merge pull request #318 from ninjin/julia

Julia support
Fix Script class name for C#
Escaping backticks
Merge pull request #318 from ninjin/julia

Julia support
use absolute path for unzipping dmd.zip
Auto-merged master into ha-feature-community-languages on deployment.
Merge pull request #340 from MartinNowak/dlang

support for the D Programming Language
Merge branch 'ha-feature-community-languages' of github.com:travis-ci/travis-build into ha-feature-community-languages
use curl with retry option and prepend Travis-CI to curl's user-agent

- the user-agent helps us to distinguish automated
  downloads from real user downloads
print community maintained language disclaimer