Addes CROMFS prototype. CROMFS is a commpressed, in-memory read-only file system based on LZF.

Squashed commit of the following:

    fs/cromfs:  Now depends on EXPERIMENTAL because it is not yet verified.
    fs/cromfs:  This commit brings the CROMFS file system to code complete.  Still completely untested.  Next steps:  Need a tool to generate CROMFS file system images and a test case under apps/
    fs/cromfs:  Add logic to traverse the in-memory file system nodes.
    fs/cromfs:  Add initial support for an in-memory, compressed, read-only file system.