Support for SMITE TFC Rendering

[yretenai]

Smite (and games with the same licensee) has stored bulk data references in a file called MergedFileIndexCache.bin.

This patch adds a Serializer for FSmiteManifest, and the necessary logic to UTexture3 to find entries in MergedFileIndexCache and read from the appropriate TFC files.

The MergedFileIndexCache is keyed to an MD5 of the full UObject path name, hence the inclusion of a MD5 library.

The reason they did this is so that it allows the publisher to patch high resolution textures without rebuilding the entire UPK file, reducing patch sizes.