Convert double-quoted strings to single-quoted strings when there is no interpolation.

3 files were modified.
Merge pull request #2 from mojotech/acre/master

ACRE suggest 1 changes to master.
Normalize hash syntax to ruby 1.9
Merge pull request #3 from mojotech/acre/master

ACRE suggest 1 changes to master.
Convert double-quoted strings to single-quoted strings when there is no interpolation.

4 files were modified.
Insert underscores into literal numbers.
Normalize hash syntax to ruby 1.9

2 files were modified.