mjcross

Results 3 issues of mjcross

Added a hint for people who build with STANDALONE=n, notably to add -L/path_to/sdk/ld to LDLIBS so that the linker can find eagle.app.v6.ld

Add an example showing how to use the PIO to control a multiplexed 7-segment display.

Proposed changes to integrate Espressif's new RMT driver