Updated phpunit version to deal with bug

When I added new tests some old ones stopped running, and this upgrade
resolves that.
Altered test to allow null returns
Made FileSystemTest extendable

Mainly by having it merge in master options with the per-test custom
ones. This allows things like overriding encoders.
Segmented Filesystem Encoding, Added New Option

This takes out the actual encoding and decoding of data out of the
filesystem class itself. Now individual encoding objects can be passed
as options, and a new option to use php serialization instead of native
objects is available.
Cleaned up data

This is from #191 submitted by @mrclay.
Corrected redis testing error
Fixed exception type.
Revert "Fixed exception type."

This reverts commit db7cc4b49a8727478059b560ec19b84cd5003540.
Revert "Corrected redis testing error"

This reverts commit f28e6b6fed3fdae14deadf0872df5305cd8e8d52.
Skip BadDisconnect error on HHVM
Merge pull request #197 from tedious/filesystem_encoding

Filesystem Encoding Methods