fixed avrfix

added some scripts to make avr-gcc on ubuntu, Debian may be work too.
buildscript for cygwin does not work now.

changes on the fixed Point library:
the #ifdef removed, as we use -ffunction-sections
These Compiler defines removed: MULK SQRT CORDICHK ROUNDKD DIVKD

changed the _Accum to _iAccum, it is in conflict with avr-gcc, as _Accum is a reserved type specifier.
there is no Problem this time, as we use avr-g++ to compile, but for future it is save to Change it.
Maybe we make sometimes a printer with an arm core that have a dsp?
see the example in avrfix.c.