Revamp deploy.py

Now the script supports more flashing methods:
- JLink (with tockloader)
- OpenOCD (with tockloader)
- pyOCD
- Nordic DFU
- none (will produce an IntelHex file)

Also merged the contributions from:
- Yihui Xiong to support the Makerdiary USB dongle board
- Dennis Geurts to support Nordic DFU

Doc updated accordingly.

Imported 2 patches for Tock kernel:
- 06-add-set_vector_table_offset.patch (upstream tock/tock#1579)
- 07-nrf52-bootloader.patch (upstream tock/tock#1681)

boards/nrf52840_dongle_dfu/Cargo.toml

@@ -0,0 +1,30 @@
+[package]
+name = "nrf52840_dongle_dfu"
+version = "0.1.0"
+authors = ["Tock Project Developers <tock-dev@googlegroups.com>"]
+build = "build.rs"
+edition = "2018"
+
+[profile.dev]
+panic = "abort"
+lto = false
+opt-level = "z"
+debug = true
+
+[profile.release]
+panic = "abort"
+lto = true
+opt-level = "z"
+debug = true
+
+[[bin]]
+path = "../../third_party/tock/boards/nordic/nrf52840_dongle/src/main.rs"
+name = "nrf52840_dongle_dfu"
+
+[dependencies]
+components = { path = "../../third_party/tock/boards/components" }
+cortexm4 = { path = "../../third_party/tock/arch/cortex-m4" }
+capsules = { path = "../../third_party/tock/capsules" }
+kernel = { path = "../../third_party/tock/kernel" }
+nrf52840 = { path = "../../third_party/tock/chips/nrf52840" }
+nrf52dk_base = { path = "../../third_party/tock/boards/nordic/nrf52dk_base" }

boards/nrf52840_dongle_dfu/build.rs

@@ -0,0 +1,4 @@
+fn main() {
+    println!("cargo:rerun-if-changed=layout.ld");
+    println!("cargo:rerun-if-changed=../../third_party/tock/boards/kernel_layout.ld");
+}

boards/nrf52840_dongle_dfu/layout.ld

@@ -0,0 +1,10 @@
+MEMORY
+{
+  rom (rx)  : ORIGIN = 0x00001000, LENGTH = 188K
+  prog (rx) : ORIGIN = 0x00030000, LENGTH = 832K
+  ram (rwx) : ORIGIN = 0x20000000, LENGTH = 256K
+}
+
+MPU_MIN_ALIGN = 8K;
+
+INCLUDE ../../third_party/tock/boards/kernel_layout.ld