also scope the \n at the end of line comments as comment.line

[keith-hall]

Fixes #123.

Note that it doesn't seem possible to create a test assertion for it until #124 is addressed, as atom-grammar-test doesn't seem to support tokens on \n characters - when I try, I just get an error:

Expected to find comment.line.powershell at 769:34, instead found no token

[omniomi]

LGTM, we can include it in the sublime tests.

I'm moving Monday so 70% of my stuff is in boxes right now and the other 30% needs to be put in boxes so it will be at least a week before I circle around to it which gives @tylerl0706 time to figure out the copyright part.

[TylerLeonhardt]

LGTM!