Note: The 1.4-2 & 1.4-3 releases never made it as released pacakges
due to build issues

Differences between 1.4-1 & 1.4-4 (2012-08-08 & 2012-09-13)
- Add 'performance' counters to all op codes. This reports the time spent in
  'usleep()' since last op code.
- Fix an off-by-one bug in LOG SELECT
- Implement ability to reset log counter via LOG SELECT & PCR bit
- Add _GNU_SOURCE define so source can be compiled on old Linux distributions

Signed-off-by: Mark Harvey <markh794@gmail.com>