Add basic dummy TargetMachine and TargetInfo
Hook up new target into llvm. Note that it will fail to build without MCDesc.
Add MCTargetDesc. Now llc can be successfully build and Simple target will be visible under --version option.
Add dummy Subtarget implementation.
Add implementation of MCAsmInfo
Add TargetLowering. Now llc should fail with 'No Integer registers defined' assert.
Add RegisterInfo. Still not functional until InstrInfo will be added.
Add InstrInfo with really simple instruction set.
Add instruction selections pass.