Since all currently supported boards use pin A9 for this function, the
value of the macro MICROPY_HW_USB_VBUS_DETECT_PIN is not actually used,
just the fact that it is defined.
Addresses issue #1048.
Pulled in and modified work done by mux/iabdalkader on cc3k driver, from
iabdalkader-cc3k-update branch. That branch was terribly messy and had
too many conflicts to merge neatly.
This renames MICROPY_HW_HAS_WLAN to MICROPY_HW_ENABLE_CC3K (since it's a
driver, not a board feature) and wraps all CC3000 code in this #if.
It's disabled for all boards.
All board config macros now begin with MICROPY_HW_.
Renamed PYBv10 to PYBV10, since macros should be all uppercase.
Made SDCARD_DETECT configurable in mpconfigport.h, so that the SD
detect pin can be easily configured.
