Update ui_widget.hpp

Minor syntax error in the README file

Added include of <functional> to allow for a clean build with g++ 7.2.1 20170904

Caused issue #114, presumably due to RDX being assigned to an unused pin, which was pulled high, and was therefore never asserted.

Thanks, furrtek!

Left over from Ubuntu Precise?

May use again, so commented out.

With help from https://github.com/ARM-software/CMSIS_5/issues/98

Using void* makes me really queasy though!

No change in function, but *may* result in tiny reduction in power and noise? Not tested.

It was poorly implemented and was confusing the hell out of people when their CPLD was showing "BAD", even though it was fine...

Just for consistency. Other LCD interface pin states are read during interrupt.

Should keep CPLD settled when in HackRF mode.

Not sure if any changes have actual significance, but...

HackRF firmware assumes state specified in user manual, where all(?) peripheral clocks are enabled.

Dropped power consumption by 42mA at VBUS -- ~200mW.

It's the only LCD write function!