Formtf

Methods which determine Base vs PC relative added. B and P bits are being set. The call to validate_operand_size in validate_tf_operand was removed as the values needed for that check to be completed are only done inside in the format handlers. Need to add the notes in the assembler's header file for process_format_3() and 4, and need_base(). 

Further error checking needs to be made regarding how the value is treated by the assembler. Base mode is being handled conservatively, with PC being used at any possible opportunity.