Recognise *.dyalog as APL sources
Add sample .dyalog file for file type APL

Taken from
https://github.com/Gianfrancoalongi/APLUnit/blob/master/UT.dyalog
Merge pull request #1632 from ngn/master

Recognise *.dyalog as APL sources
Add F# sample.  Add Forth extension .fs.