Allow the configuration of "acceptable errors"

Assets are not included if the dispatch error is not in whitelist of
allowed errors.
The BjyAuthorize module throws a \BjyAuthorize\Guard\Route::ERROR
error, which should still include assets
Merge pull request #54 from rhysr/acceptable_errors

Allow the configuration of "acceptable errors"
added acceptable errors docs
Merge pull request #55 from rhysr/acceptable_errors

added acceptable errors docs
Update README.md
Ensure we check the result of `strpos()` correctly
Merge pull request #58 from dshafik/strpos-returns-boolean

Ensure we check the result of `strpos()` correctly
update tests
Fixing problem with mixin check
Merge pull request #59 from evelop/master

Mixin config does not work as intended
configuration param to override the umask
Merge pull request #60 from tommyseus/master

Option to set the umask
optional filters in debug mode
Merge pull request #61 from tommyseus/master

optional filters in debug mode
Update .travis.yml
changed order of default config inclusion
Merge pull request #62 from aroos/master

Changed order of default inclusions