Merge branch 'release-2.3.2'
make flash middleware implements countable
Merge remote-tracking branch 'lalop/flash_countable' into release-2.3.3
Bump version numbers
Bump version numbers
Add HHVM compatibility
Fix unit tests for HHVM
Remove vagrant files
Fix PrettyException middleware when custom log defined
Don't send any content when it's a HEAD request.
Add hhvm configuration example to README

Fix inline doc versions in a few class files
Fix README typo
Fix merge conflicts with release-2.3.3
Add Pimple container class
Add Collection class and tests
Let View extend Collection
Let Session extend Collection
Let Http/Cookies extend Collection
Let Environment extend Collection
Update Flash to use new Session interface

Update Flash inline docs