Add support for Pan Language

As found in repositories related to @quattor, e.g. https://github.com/quattor/template-library-core
The test file provided matches the one I submitted to Pygments.

At some point in the future when the Pygments patches land at GitHub the lexer should be updated from "Text only" to "pan".
Added the General Algebraic Modeling System (GAMS) to languages, with example
Update languages.yml

Adding Ox to the list http://www.doornik.com/ox/
Update languages.yml

added explicit lexer
Merge branch 'master' of https://github.com/github/linguist into add-ox
Fix Ox implementation

Remove .h from Ox, fix `lex` typo, and add samples for Ox.
Merge pull request #1228 from christianbundy/add-ox

Add Ox
Merge branch 'master' into 1206

Conflicts:
	lib/linguist/samples.json
Merge pull request #1230 from github/1206-update

1206 update
Merge pull request #1209 from jkeirstead/GAMS-language

Added the General Algebraic Modeling System (GAMS) to languages with example
Samples update