upadate readme
Including new extensions .us and .jst

Docs say us and jst are supported for Underscore templates,
but the mapping was wrong.
Fixed task asynchrony

- Grunt needs to be told that the task is async, otherwise the result of
the task won't occur at the appropriate location in the build process
- Editor trimmed a little whitespace
Removed stray } from package.json

- Not sure how this even worked!
- Removed extraneous whitespace
Merge pull request #2 from Iristyle/patch-1

Including new extensions .us and .jst
Update README.md

fix non-uniform css_url
merge
bump package version
Minor tweak for 0.4.0 compatibility

With note to remove once 0.4.0 goes live
Merge pull request #3 from Iristyle/patch-2

Minor tweak for 0.4.0 compatibility
bump version and remove npm.log
Clean up template task
bump version
learn to spell
Added support for dynamic variables
Added to README
Merge pull request #5 from twolfson/dev/support.dynamic.variables

Add support for dynamic variables
Bump version
Correct README to make dynamic variables clear as to use (return an object).
Merge pull request #6 from plumlee/master

Correct the dynamic variables example