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".
Merge branch 'master' into 1206

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

1206 update