Adding some hacks to attempt to support the igbinary serializer when storing (and therefore transmitting) data in mongodb.

However, it appears that mongodb requires UTF-8 content, so I don't believe this will work at the moment.
Adding support for using the igbinary serializer with a file cache so that NFS operations have to transmit less data and the CPU has less work to do.
stop stripping . characters from my cache paths - i like to include the vhost name
Merge branch 'patches/file-cache-igbinary-serializer-support' into MOODLE_26_STABLE-local
Merge branch 'patches/mongodb-cache-igbinary-serializer-support' into MOODLE_26_STABLE-local