Merge pull request #126 from matthewd/automatic_dependencies

Instead of complaining, add the dependency automatically
Like Sprockets itself, clear the cache when this gem updates

To do so cleanly, fix the fact we don't have a VERSION constant.
Merge pull request #127 from matthewd/helper_version

Version the gem's helpers; if they change, the cache must go
Setup gem properly
Load Action View so hooks work
Remove unneeded comment
Remove wrong comment
Test with released version
Define railties as development dependency
Check precompile for the asset's logical_path

.. not whatever source we were originally given, which may be missing an
extension.

In doing so, we must also ensure that when we look up an asset from an
extensionless name, we end up with the one we intended -- so
check_errors_for should pass a :type through.

Fixes #128.
Merge pull request #129 from matthewd/precompile_extensions

Check precompile for the asset's logical_path
Precompile configuration now lives in an initializer

Update the error message to match rails/rails#14689.

Even if the user doesn't currently have this initializer, they can
safely create it with the supplied content, and all will be good.
Merge pull request #130 from matthewd/assets_initializer

Precompile configuration now lives in an initializer