Also ignore extern(al)

...because some of us don't like 'vendor'
Remove DCPU-16 ASM language
Merge pull request #1309 from github/gameover-0x10c

Gameover 0x10c
Add tests for extern(al) being vendored
Merge pull request #1305 from neersighted/patch-1

Also ignore extern(al)
Add a multitude of Forth file extensions.
Yes, these are all in use.
Add Groff sample.
Update samples.json.
Make test_pedantic accept quotes around extensions.