IO: Make Mode enum into enum class to fix problem with ATtiny.
Merge branch 'develop' into feature/stm32_fsmc
Comments describing the S75 example.
Change example back to use FSMC
Remove A23 as it is not used in example.
Add explanation about A16 and offset 0x20000
Siemens S75 display tested at LPCxpresso LPC1114

No LPC11C24 found so test done on LPC1114