Added support for LilyGo T-Echo

boards/t-echo.json

@@ -0,0 +1,62 @@
+{
+	"build": {
+	  "arduino": {
+		"ldscript": "nrf52840_s140_v6.ld"
+	  },
+	  "core": "nRF5",
+	  "cpu": "cortex-m4",
+	  "extra_flags": "-DARDUINO_NRF52840_PCA10056 -DNRF52840_XXAA",
+	  "f_cpu": "64000000L",
+	  "hwids": [
+		[
+		  "0x239A",
+		  "0x8029"
+		]
+	  ],
+	  "usb_product": "NRF52 DK",
+	  "mcu": "nrf52840",
+	  "variant": "pca10056",
+	  "bsp": {
+		"name": "adafruit"
+	  },
+	  "softdevice": {
+		"sd_flags": "-DS140",
+		"sd_name": "s140",
+		"sd_version": "6.1.1",
+		"sd_fwid": "0x00B6"
+	  },
+	  "bootloader": {
+		"settings_addr": "0xFF000"
+	  }
+	},
+	"connectivity": [
+	  "bluetooth"
+	],
+	"debug": {
+	  "jlink_device": "nRF52840_xxAA",
+	  "onboard_tools": [
+		"jlink"
+	  ],
+	  "svd_path": "nrf52840.svd"
+	},
+	"frameworks": [
+	  "arduino"
+	],
+	"name": "LilyGo T-ECHO",
+	"upload": {
+	  "maximum_ram_size": 248832,
+	  "maximum_size": 815104,
+	  "require_upload_port": true,
+	  "speed": 115200,
+	  "protocol": "jlink",
+	  "protocols": [
+		"jlink",
+		"nrfjprog",
+		"stlink",
+		"cmsis-dap",
+		"blackmagic"
+	  ]
+	},
+	"url": "https://os.mbed.com/platforms/Nordic-nRF52840-DK/",
+	"vendor": "Nordic"
+  }