Track bugfixes in kohana/core
Remove redundant phpenv rehash from travis build

This is only required if using PEAR packages, and should
have been removed in ec9c1b2
Temporarily run tests without phing on HHVM

Phing doesn't yet support HHVM, so run tests directly
in this environment. This can be reverted in future
once we can run phing (hhvm support is planned for
2.9.0).
Update to latest cache 3.3/develop to fix APC test failures on HHVM

HHVM was failing because the apc extension is installed there, and
the cache module unit tests failed if APC was present with no valid
configuration.

The cache module itself requires further updates to the build process
and environment to get the other skipped driver tests running and to
get APC tests running on PHP 5.x
Update to latest core 3.3/develop to fix HTTP_Header issues on HHVM

See kohana/core@ce8288f - ArrayObject does not behave as expected
on HHVM.
Update to latest core 3.3/develop to fix Date issues on HHVM

See kohana/core@952d6a8 - DateTime may return incorrect timezone
on HHVM if it was created with a timestamp or offset in the date
string.
Merge pull request #44 from kohana/bug/3.3/build-fixes

Resolves build failures for the 3.3 branch - travis is now green on all environments.