Basic functionality works now with asm
- Add preprocessor defines for registers
- rename si2cCheckAddress.S to si2cSlaveCheckAddress.S
- rename si2cWaitInit.S to si2cSlaveWaitInit.S
- remove double named c-function "si2cSlave"
- remove si2casm.S and move the functions to si2cAdditional.S and si2cSCL.S