Update tests and README.md to reflect discussion w/ Sprockets team (https://github.com/sstephenson/sprockets/pull/560) that manifest filename must be explicitly specified by user.
Clarify wording in readme
Update CHANGELOG.md
:uglify -> :uglifier
Merge pull request #141 from braddunbar/uglifier

:uglify -> :uglifier
Ensure supplied asset paths don't contain "/assets/"

This is a somewhat common error, and an easy way to end up with missing
digests in production.
separate precompile tests from manifest tests
write failing test for AssetUrlHelper helpers
alias path_to_asset to asset_path with error checking
write failing test for debug mode
don't check for required assets in precompile array in debug mode
make non-javascript and non-stylesheet assets match filter
remove unneeded code causing precompile errors
don't check runtime errors for other tests
Ignore missing dependencies, instead of failing

Arguably, Sprockets should be capable of depending on a non-existent
filename, so it knows our content would change if it appeared.

But for now, carrying on silently is the best we can do.
Merge pull request #144 from matthewd/ignore_missing_dependencies

Ignore missing dependencies, instead of failing
Merge pull request #142 from matthewd/absolute_asset_path_error

Ensure supplied asset paths don't contain "/assets/"
assets version doesn't depend on asset host iff it's a Proc
Merge pull request #140 from pomnikita/fix-assets-version

assets version doesn't depend on asset host if it's a Proc
Merge pull request #143 from dskang/js-css-path

Use `asset_path` with error checking for all calls to `path_to_asset`