Don't install phing from PEAR on travis - we have it in composer

The composer.json was updated in daf1e3d to install phing as a composer
package. It's therefore already on our travis instance (in vendor/bin)
without also needing to install from PEAR.

This resolves build errors on hhvm (where pear is not installed by
default) and reduces build time on other environments.
Prefer composer distribution downloads for travis build

Speed up build time by preferring to download archives rather than
cloning repos when building on travis.
Track latest 3.3/develop of kohana/core to fix failing tests
Merge pull request #43 from kohana/bug/3.3/build-fixes

Fix travis build and test execution