Fixed Freescale byte reads (minus k64)

See:
https://mbed.org/questions/3181/Inconsistent-results-when-attempting-wri/
for the issue. Now every byte read is treated equal and ACKs/NACKs are
correctly generated
I2C changes for the K64F

Fixed also here single byte read (probably)
Merge branch 'master' of https://github.com/Sissors/mbed into Sissors-master
make sure we remove any function from a physical pin so that we can assign a new function to it.
Merge branch 'Sissors-master'
Merge branch 'master' of https://github.com/mbedmicro/mbed