Pitrex IO Lib Changes for R0.2.3: *Modified to work with UART1 by default, or UART0 if "UART0" is defined during compilation. *Uses local bcm2835 library file (eg. bare metal version). *Possibly other minor modifications to equate to the modifications that Malban made to V. 0.1. R0.2.2: *Fixed infinate loop in vectrexread, vectrexread_on_irq, vectrexwrite, vectrexwrite_on_irq if invalid address provided. R0.2.1: * Add parameter to vectrexinit() that makes it initialise the VIA as well as the PiTrex/GPIO. -DONE * Separate read and write operations so that completion can be checked after operations begun, by checking the status of the EDR. -Now need error handling for invalid addresses so that not waiting on canceled write to complete. -DONE * Same approach to interrupts. -DONE * Interrupt loops only respond to specified interrupt read from IFR after #IRQ asserted. -DONE * Optimised read and write functions for sequential operation. - forget it, or for later * Comment out USE_EDR definition to allow option to be passed compiler with the compilation command. -DONE