fix seeding performance issue when multiple threads are reading the same piece
make some graphs use nicer gradients in session stats
don't evict pieces with read jobs hanging on them
some cleaning up of read_job lists on cached_piece_entry in an attempt to make sure they don't leak
support condition_variable::notify()
clean up settings preset backwards compatibility functions
fix settings issue with pool allocator for the disk thread
fix for running job accounting
log appropriate values in hex
improve gradient in session stats reports
filter rate stats updates in client_test log
use notify instead of notify_all
disk cache stats fixes + some documentation
move performance counters out of session_interface into its own class, counters