Fix phpdocs

Mostly fully qualified namespaces, incorrect classes or wrong/missing
return values.
Throw exceptions on URL::action when action not found. Fixes #1097.
Check for hash in "isValidUrl". Closes #1074.
Added ability to pass `Closure` as third parameter to `Route::model` to determine not found behavior. Closes #1062.
Remove intended location from session before redirect.
Merge pull request #1110 from bonzai/master

Remove intended location from session before redirect