Add Tcl/Tk interpreters to languages.yml for shebang detection
Add sample Tcl/Tk scripts to test Tcl/Tk shebang detection

Scripts taken from:
* starfield: http://wiki.tcl.tk/14140
* owh: http://wiki.tcl.tk/906
Move the extension-less sample scripts in a filenames/ subdir
Add .fcgi as an extension for script languages
Docs update
Formatting
:scissors:
Merge pull request #1605 from github/bkeepers/gitattribute-docs

Suggested cuts for .gitattribute docs
Merge pull request #1602 from github/gitattribute-docs

Docs update
Require "bundler/setup" in rakefile

This ensures that the Rake task will use bundler to manage dependencies and print a warning to run `bundle install` if dependencies are missing.
Moving Rugged dependency back to gemspec
Merge pull request #1610 from github/rugged-gemspec

Moving Rugged dependency back to gemspec
twiddle-wakka
Merge pull request #1611 from github/rugged-gemspec

twiddle-wakka
Merge pull request #1609 from github/bundler-rakefile

Require "bundler/setup" in rakefile
Merge pull request #1596 from pchaigno/fcgi

Add .fcgi as an extension for script languages
Merge pull request #1584 from laomaiweng/linguist-detect-tcl-shebang

Shebang detection for Tcl/Tk scripts
Add a filename rule for _vimrc
Merge pull request #1614 from creasty/viml_underscore_vimrc

Add a filename rule for _vimrc
Add a multitude of Forth file extensions.
Yes, these are all in use.