Many odex fixes and checks.

ADDED:
  - Added Adler32 checksum parsing for odex contents.
  - Added reading class descriptor inside odex sections.
FIXED:
  - Odex parsing in general, offsets where not being properly
    padded, now they are.
  - File size attribute is not properly parsed and checked for
    odex files.
  - Fixed the Alder32 and SHA1 checks when file is odex, significant
    speed increases in doing so.
  - SHA1 should just not be run against Odex since it should always
    fail.