Add consistent (by filename/path) sort on hashes

To avoid randomization in version control, it's best to have a
consistent order of results in the assethash JSON object between runs,
even if the source files don't change.

This commit adds a step to the file output process to re-order the JSON
object based on sorting the keys.
clean a little bit
add a usage example
Fix jshint issues
Add tests for sorted output JSON objects

Given an input in an arbitrary order, confirm the output is sorted based
on filename.
Merge pull request #2 from dpolivy/bug/1

Add consistent (by filename/path) sort on hashes
drop stat.blksize dependency; update grunt version; format output json
Merge pull request #3 from ktmud/fix-test

drop stat.blksize dependency; update grunt version; format output json
bump to 0.1.4