Add test for lines with trailing whitespace.

Trailing whitespace should not interfere with normal indentation algorithm.
Emit semicolon in case of trailing whitespace.

Lines ending like `\s+$` should not impact indentation of subsequent
lines. Instead, the trailing whitespace should be tokenized as if it
didn't exist.
Add file-local variable to avoid whitespace cleanup.
Merge pull request #99 from elixir-lang/tokenize-whitespace-eol

Tokenize trailing whitespace properly. Fixes #97
Add failing test for multiline case.
Add '->' as a MATCH-STATEMENT-DELIMITER.
Change test names for consistency.
Switch to using rx for other regex.
Flesh out rules for MSD.
Remove problematic cond expression.
Add fn to test if inside match block.
Emit match stmt delim if condition passes.
Add MSD line-end check to backward token as well.
Emit '->' directly at start of match stmt.
Remove unnecessary args to 'looking-back'
Fix bug in semi-ends-match fn.
Multiline match indentation is fixed.

However a couple other tests fail now. Progress!
Add fn for comparing line numbers.

Elixir is quite flexible wrt syntax around the `->` token. It can follow
`do` or `fn`, either on the same line or separately. Because of this, a
function that can detect whether it's on the same line as its parent was
needed.

After adding this function, all tests passed. I'm skeptical about the
robustness of this function but it will have to be battle hardened by
users reporting bugs.
Add another multiline match test.

This time separate the match clauses by a blank line. This test fails.
Fix bug in match-ending detection fn.