Auto build and a couple pin fixes

Author: tannewt

.travis.yml

@@ -21,7 +21,7 @@ git:
 # that SDK is shortest and add it there.  In the case of major re-organizations,
 # just try to make the builds "about equal in run time"
 env:
-  - TRAVIS_TESTS="unix docs translations" TRAVIS_BOARDS="feather_huzzah circuitplayground_express pca10056 pca10059 feather_nrf52832 feather_nrf52840_express makerdiary_nrf52840_mdk" TRAVIS_SDK=arm:nrf:esp8266
+  - TRAVIS_TESTS="unix docs translations" TRAVIS_BOARDS="feather_huzzah circuitplayground_express grandcentral_m4_express pca10056 pca10059 feather_nrf52832 feather_nrf52840_express makerdiary_nrf52840_mdk" TRAVIS_SDK=arm:nrf:esp8266
   - TRAVIS_BOARDS="metro_m0_express metro_m4_express pirkey_m0 trellis_m4_express trinket_m0" TRAVIS_SDK=arm
   - TRAVIS_BOARDS="feather_radiofruit_zigbee gemma_m0 hallowing_m0_express itsybitsy_m0_express itsybitsy_m4_express meowmeow" TRAVIS_SDK=arm
   - TRAVIS_BOARDS="feather_m0_express_crickit feather_m0_rfm69 feather_m0_rfm9x feather_m4_express arduino_zero arduino_mkr1300" TRAVIS_SDK=arm

ports/atmel-samd/boards/grandcentral_m4_express/pins.c

@@ -60,7 +60,6 @@ STATIC const mp_map_elem_t board_global_dict_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_D21), (mp_obj_t)&pin_PB21 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_SCL), (mp_obj_t)&pin_PB21 },
 
-    // Not connected but probably should be.
     { MP_OBJ_NEW_QSTR(MP_QSTR_D22), (mp_obj_t)&pin_PD12 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_D23), (mp_obj_t)&pin_PA15 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_D24), (mp_obj_t)&pin_PC17 },
@@ -123,7 +122,7 @@ STATIC const mp_map_elem_t board_global_dict_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_SD_CS), (mp_obj_t)&pin_PB28 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_SD_MISO), (mp_obj_t)&pin_PB29 },
 
-    { MP_OBJ_NEW_QSTR(MP_QSTR_SD_CARD_DETECT), (mp_obj_t)&pin_PB21 },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_SD_CARD_DETECT), (mp_obj_t)&pin_PB31 },
 
     { MP_OBJ_NEW_QSTR(MP_QSTR_NEOPIXEL), (mp_obj_t)&pin_PC24 },