Pyocd

- pyDAPAccess addition (replacement for the old interface and transport layers)
- gdbserver
- add `init` and `reset` functionality
- reset halts
- new boards addition
- mbed lpc1114, nrf51 dongle, mbed TY51822r3, mbed HRM1017, RedBearLab-nRF5182, RedBearLab-BLE-Nano, Seeed-Tiny-BLE, u-blox-C027, switch science mbed lpc824, lpcxpresson 824max, microbit
- tests
- dynamically get board attributes, add test summary

- semihosting support
- fix pyusb dependency
- internal improvements - cortexM hw/sw breakpoints, changes in gdb server (new commands, Packet thread class)