Options in outputCss and outputJs methods

Allowing to acccept CollectionName parameter in outputCss and outputJs method. 

Phalcon docs:
public outputCss ([string $collectionName])
public outputJs ([string $collectionName])
http://docs.phalconphp.com/ru/latest/api/Phalcon_Assets_Manager.html
Update $options as optional parameter

$options as optional parameter to preserve compatibility
Try to fix Travis build
Merge pull request #236 from AlexKomrakov/patch-1

Options in assets outputCss and outputJs Twig methods
Updated Readme to fix issue #239

Updated Readme to fix issue #239: https://github.com/phalcon/incubator/issues/239
Merge pull request #240 from JavaDevVictoria/master

Updated Readme to fix issue #239