waverplayer RTOS demo - at present time older libraries were needed to avoid SD open errors - so don't update them

Dependencies:   SDFileSystem_OldbutworkswithRTOS mbed-rtos mbed wave_player

Fork of WavePlayer_HelloWorld by jim hamblen

This is a demo of the waveplayer using the RTOS on an SD card. I had to use older libraries to get it to work as of 4/18/17 on the LPC1768. Updating libraries adds a lot of compiler warnings about filesystem stuff, and it seems to cause SD card open errors.