Remove unnecessary complexity from getHelpers.
Remove unused _mix`
Add back intlBlock
Add currency to hash for message formatting
Fix errors.
Fix currency storage. Store context data for intlBlock calls.
Pass Intl as factory param.
New tests --needs work with the names.
Remove _data. Correct context __proto__. Add IntlMessageFormat as a
second argument to the factory.

Remove `_data` usage. This is unnecessary after the context was
corrected.

Added comments to the format  option methods.
Update handlebars version for tests
Add nested tests.
Add in `extend` helper to avoid augmenting the options.hash
Merge branch 'master' of https://github.com/yahoo/handlebars-helper-intl into currency

Conflicts:
	index.js
	tests/helpers.js
Change documention for extend to clarify it is a utility method only.
Add comment describing params passed to factory