Added .inc extension in Assembly group.

It`s include file for assembler source that helps to structure code. Usually contains normal assembly source.
Added examples for Assembly

From FASM source under BSD
Rename ASSEMBLE.INC to ASSEMBLE.inc
Rename FASM.ASM to FASM.asm
Rename SYSTEM.INC to SYSTEM.inc
Rename X86_64.INC to X86_64.inc
Merge pull request #1268 from metopa/patch-1

Support of the .inc extension in Assembly group.
Samples
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.