add Avalon A3255 prototype machine support
update with new fpga firmware 2013-11-08 for Avalon 55nm prototype
 FPGA controller URL: http://downloads.canaan-creative.com/hardware/A3255/prototype/FIRMWARE/2013-11-08/FPGA/
Use defines instead of 110 or 55
Merge branch 'avalon2-prototype' of https://github.com/BitSyncom/cgminer into ava2
Make the result return rate low detection on avalon less trigger happy.
Use an equation instead of a lookup table to set the frequency for 55nm avalon allowing arbitrary values to be used.
55nm avalon requires the delays between writes reinstated for stability.
Modify the auto tuning sequence to work with the 50MHz changes required to work with 55nm Avalon.
Update documentation for modified avalon options syntax and document relevant 55nm details.