First pass at making TMP files for build outputs.

Instead of sending headers which can easily be ignored, store build
results in TMP. These build outputs can easily be re-used until their
components change.

Refs #218
Trim down variables.

Use local vars to require fewer array offset calls.
Write built resources so they can be read later.
Add tests for build output caching.

Add tests to ensure build output is stored on disk for future use.
Have console tool clear new temporary cache files too.

The clear command should clear all the temp files too. Its only polite
really.
Merge branch 'master' into cache-builds
Tweak how development cache files work.

* Put files in cache/asset_compress.
* Don't store cache files with timestamps. Having timestamps on
  makes finding files later a pain.
Merge pull request #219 from markstory/cache-builds

Cache build outputs