Constants workaround
Merge pull request #1579 from Cinderella-Man/2.0.0

[2.0.0] Constants workaround
Fixing unused variables [ci skip]
Random updates to version 2.0
Add Queue [ci skip]
Merge pull request #1583 from Cinderella-Man/2.0.0-random-fixes

2.0.0 fully compiled and running
Readme for Phalcon 2.0 contributors
Merge pull request #1590 from Cinderella-Man/2.0.0-travis-try

[2.0.0] Travis CI up to speed
Fixing undefined functions [ci skip]
Zephir compile Queue [ci skip]