Cleanup Scale, particularly the weird polymorphic output of getCombinedExtent.
Rename autorangeDomain to autoDomain.
Close #301.
Fix #321
use capital case for static constants
Merge pull request #320 from palantir/cleanup-scale

Cleanup Scale, particularly the weird polymorphic output of getCombinedE...
Merge pull request #323 from palantir/capcase

use capital case for static constants
fix ff failures in axisTests
Merge pull request #327 from palantir/unittests

fix ff failures in axisTests
Merge branch 'master' into bar-renderer-merge

Conflicts:
	src/renderers/categoryBarRenderer.ts
Some streamlining and API changes on BarRenderer, add CategoryBarRenderer back in to ease transitions.

CategoryBarRenderer is just an alias for BarRenderer, but logs a message
in the console telling the developer to just use BarRenderer.