added ads1298_driver files - initial add
rreg and wreg can parse register and values in hex now
ads1298_driver can now read registers
ads1298_driver can now write registers
ads1298_driver can now send samples continuously (RDATAC) and stop sending (SDATAC)
rdata command works; some code cleanup
initial addition of python performance test for ads1298 driver
minor optimizations - can now reach about 2200 samples per second
minor performance optimization - still around 2k SPS
minor optimizations - with pypy it does about 10k sps
can do 8k samples per second using pypy