cointerra: Import driver from cgminer as-is

cgminer commit: a3e3957809e358aeb2872f56a8e48db6cfc94051
Build cointerra driver
cointerra: Replace reset semaphore with a simple notifier
cointerra: Remove nodev checks for now
Add api_add_int16 to API functions.
Provide a copy_work_noffset function for copying a work struct but changing its ntime.

Conflicts:
	cgminer.c
	miner.h
Export share_diff function and add flip12 macro
Provide a function to discard queued work based on age.
Export the flush_queue function for use by drivers.

Conflicts:
	miner.h
notifier_wait, notifier_wait_us, and notifier_reset functions
lowl-usb: Cleanup dead code
cointerra: Dirty BFGMiner port
cointerra: Wait for info packet on probe
cointerra: Divide up processors
README: Explicitly mention automatic solo mining configuration, and stress the importance of --coinbase-sig
cointerra: Cleanup debugging
Remove dead CPU mining code to silence warnings
Bugfix: Always call enable_pool and disable_pool to ensure consistent handling of the situations
Call disable_pool() at the begin of remove_pool() and combine them when appears together in the code

Signed-off-by: Huang Le <4tarhl@gmail.com>
Combine reject_pool into disable_pool function, and don't allow it to override a manual disable

Signed-off-by: Huang Le <4tarhl@gmail.com>