State of the Controlix source tree

Lots of changes to the source tree over the past week, mostly cleanups; but, the important one is this: FreeRTOS is out, RT-Thread OS is in. FreeRTOS was taking too long for me to get the whole thing working - I had spent months on trying to get it and the associated FreeRTOS+POSIX pthread support library to build and link properly, and I never did get it to run with a "Hello, World" type of example. RT-Thread was fully working with the "Hello, World" example running properly with the Linux/POSIX simulation target in less than a week! It is a good thing I came across it while searching Wikipedia for a list of open source RTOSes which supported pthreads. Hats off to the developers - the only issue is that the dev community for it is almost all Chinese, which makes it a bit difficult at times to find documentation, lists of bugs, etc. Still, the source code and build system is so clean, neat and organized compared to FreeRTOS that I didn't need to refer to much other than it to get everything up and running. Happy!