front: Remove some more leftover stuff.
front: Properly refresh action bar on front screen.
front: Differentiate homebrew rom headers from null rom headers.
front: Add a class for faster lookup of rom goodname by crc.

For the complete goodname, e.g.
  Legend of Zelda, The - Majora's Mask (E) (M4 (V1.0)[!]
you need the MD5 checksum, which takes a few seconds to compute.

If you don't need or want all the extra tags, e.g.
  Legend of Zelda, The - Majora's Mask
you only need the ROM crc, which is much cheaper to compute and makes
the UI more responsive.

This class allows you to lookup by crc, and will later house other
lookups, like cover art, rumble capability, number of players, etc.

The MD5-based lookup may still be necessary in certain places where the
version info is important.  Perhaps save/slot/sram data.
front: Use the good name rather than header name in front screen.