Merge test cases
Specify dev dependency versions
Make all tests follow same format
Move inherits to regular dependencies
Move all dotted dir names to hyphens
Remove unneeded benchmark.js file

It appears that the benchmark.js file is unneeded, since the benchmarks
are run by `matcha` and stored in the `benchmarks/` folder. The
benchmark.js file doesn't even run on node v0.10 anyway.
Merge pull request #49 from reworkcss/remove-bench

Remove unneeded benchmark.js file
Merge pull request #48 from reworkcss/test-cases

Normalize test cases
Optionally return the SourceMapGenerator directly

Returns the SourceMapGenerator object without serializing to JSON when
`sourcemap: 'generator'` is specified. Closes #41.