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)

patches/tock/06-add-set_vector_table_offset.patch

@@ -0,0 +1,23 @@
+diff --git a/arch/cortex-m/src/scb.rs b/arch/cortex-m/src/scb.rs
+index 8107f16..a271db9 100644
+--- a/arch/cortex-m/src/scb.rs
++++ b/arch/cortex-m/src/scb.rs
+@@ -9,7 +9,7 @@ use kernel::common::StaticRef;
+ struct ScbRegisters {
+     cpuid: VolatileCell<u32>,
+     icsr: VolatileCell<u32>,
+-    vtor: VolatileCell<u32>,
++    vtor: VolatileCell<*const ()>,
+     aircr: VolatileCell<u32>,
+     scr: VolatileCell<u32>,
+     ccr: VolatileCell<u32>,
+@@ -54,3 +54,8 @@ pub unsafe fn reset() {
+     let reset = (0x5FA << 16) | (aircr & (0x7 << 8)) | (1 << 2);
+     SCB.aircr.set(reset);
+ }
++
++/// relocate interrupt vector table
++pub unsafe fn set_vector_table_offset(offset: *const ()) {
++    SCB.vtor.set(offset);
++}
+