Install headers in separate directory.
Related changes:
- Patch for Kenwood TruX drives (they worked before, but were very slow)
- Slightly different default read command to alleviate end-of-track
read problems on a number of drives
- New -z command syntax; option argument to allow a skip after a
user-configurable number of tries
- Added more possible read commands to autoprobe
- Removed autoprobe limitation, so starting a new rip will not
potentially stall in autoprobe until previous rip finishes
- Patch to allow sample-granulairy offset
- allow NULL callbacks to be passed to library interface