YAML file recognition for Inform 7, an interactive fiction design language.

The team account https://github.com/i7 has several active Inform 7 projects.
Inform has long lines, so we line wrap.
Merge branch 'master' of https://github.com/github/linguist
Added a lexer definition (text only).
I may build an Inform 7 highlighter/lexer someday, but not this week.
Add .vshader, .fshader, .gshader files for GLSL.
Oops, looks like this has to be alphabetical...
Merge pull request #1073 from tajjada/master

Add .vshader, .fshader, .gshader files for GLSL.
Merge pull request #897 from erkyrath/master

YAML file recognition for Inform 7
Updating samples
Adding Crystal samples to address https://github.com/github/github/issues/24802
Merge pull request #1109 from github/adding_crystal_samples

Adding Crystal samples to address https://github.com/github/github/issue...
Merge remote-tracking branch 'upstream/master' into fix-mercury-vendor-dirs