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
Merge pull request #1584 from laomaiweng/linguist-detect-tcl-shebang

Shebang detection for Tcl/Tk scripts