Refactoring of 1-wire driver
Addis boilerplate for Inter Process Communication
Add new command in 'cmd'
Bugfix for 1-wire driver
Added support for IPC command PERIPH_DETECT
Added support for abstract timer

Software layer on timer1 to be able to use multiple
timers simultaneously.
Major updates

* SPI abstraction
* 1-Wire asynchrone support
* Improved RTC support
* Initial IPC support
* Support for reset reason
Bugfix in delay calculation in Timer1
Timer supports 32 bit timekeeping
Added first draft on list implementation
Updates in main program
Updates for uart when integrating on HW 2.4A
Changed F_CPU to 8MHz for board bringup
Added support for setting RTC clock
Added *.out to .gitignore
Moved header files to include
Enabled external memory interface

This patch enables 32kB of external SRAM.
Stack is located in internal RAM and starts at address
0x2200 and grows toward address 0x0000.
Heap starts just above stack and grows to 0x9fff.