Add automatic switching to the PYNQ Microblaze i2c library (#1137)
Add automatic switching to the PYNQ Microblaze i2c library (#1137)

Fixes: Xilinx/PYNQ-Dev#284
schelleg/PYNQ,cathalmccabe/PYNQ,schelleg/PYNQ,cathalmccabe/PYNQ,schelleg/PYNQ,cathalmccabe/PYNQ,Xilinx/PYNQ,Xilinx/PYNQ,Xilinx/PYNQ,yunqu/PYNQ,cathalmccabe/PYNQ,yunqu/PYNQ,Xilinx/PYNQ,schelleg/PYNQ,yunqu/PYNQ,cathalmccabe/PYNQ,schelleg/PYNQ,Xilinx/PYNQ,yunqu/PYNQ,yunqu/PYNQ,cathalmccabe/PYNQ