LPC31: Configuration and build support for a forthcoming USB host driver; configs/ea3131/nsh converted to use kconfig-frontend tools

Various fixes from initial attempts to integrate the SAMA5 SSC/I2C driver with the I2C character driver loopback test

Moved audio/buffer.c to libc/audio/lib_buffer.c so that it can be shared betweent he OS and applications in a kernel build

VS1053 worker thread stack size is now configurable;  Worker thread is named via pthread_setname_np().  From Ken Pettit