Move commands into their own 'api' module
Rename 'jspot.potter' to 'jspot.pot' to be more consistent with 'jspot.json'
Use defaults in api
Store defaults in a single module accessed by the other modules instead of defaults everywhere
Do cli header arg parsing in cli module, not api
Use UTC for .pot time headers
Merge branch 'develop' into feature/issue-13-make-jspot-usable-programatically

Conflicts:
	lib/extract.js
Merge branch 'feature/issue-13-make-jspot-usable-programatically' into develop
Refactor jspot's api to put everything in its right place
Move file assertion and tmp dir test helpers into a helpers module
Add a test for jspot.json
Add tests for jspot.extract
Test stubs for jspot.extractors
Tests for jspot.extractors
Check for unsupported formats before extracting
Fix bad test descriptions for js extractor tests (result of bad search and replace)
Add handlebars extractor
Add hbs extractor tests
Merge branch 'JSteunou-issue-11-handlebars-extractor' into develop
Bump version: v0.2.0 -> v0.3.0