merged fix from RC_0_16
merged python binding update from RC_0_16
merged python fix from RC_0_16
merged python binding fix from RC_0_16
merged changes from trunk
fix settings initialization issue
use just 'libtorrent' as name of error_category
fix deadlock introduced when putting queued read jobs straight into the cache. now, all completed jobs are deferred until the job causing them to complete is done, which simplifies all locking
fix build with IPv6 disabled
one more IPv6 (for when it's disabled)