Add tmp to gitignore for testing out examples.
Pull out js recipe.

* factor out a module for declarative building of gulp js tasks.

Same idea here as with the less recipe: we want a seperate module and
with a declarative interface for configuring plugins in a gulp task.
We've got a couple more options this time... declarations for angular,
hinting, uglify, sourcemaps and browserify.
Fix a couple errors in the less recipe.

* document two destinations (build, optional compile)
* fix comple destination error.