FpDebug for Linux AARCH64

[Martin_fr]

An early BETA has been added to support Linux AARCH64.

Currently working should be:
- breakpoint
- stepping (however step out may in some cases not work)
- locals/watches/hint
- stack (however on the begin/end line of a function (or in optimized code) some frames may be skipped)

NOT working
- function calling in watches
- watchpoints
- modify variables
- not tested: catching and stepping after exceptions
- asm window
...


AARCH64 Windows hasn't been started yet. No schedule exists yet.