avr/usb/rndis: Large refactoring/cleanup.

Removed a lot of jackdaw-specific stuff and made it more flexible.
Merge branches 'pull-requests/core-net-bridge-mode', 'pull-requests/core-net-resolv-bonjour', 'pull-requests/core-net-uip-loopback', 'pull-requests/cpu-avr-avrdude-mcu', 'pull-requests/cpu-avr-bootloader', 'pull-requests/cpu-avr-gc-sections', 'pull-requests/cpu-avr-rf230bb-cleanup-hooks', 'pull-requests/cpu-avr-rndis-refactor', 'pull-requests/cpu-avr-usb-cdc-serial-update', 'pull-requests/cpu-native-eeprom', 'pull-requests/cpu-native-osx-route', 'pull-requests/makefiles-uip-conf-ipv6-zero', 'pull-requests/platform-avr-ravenusb-httpd-isused-fix', 'uip-updates', 'pull-requests/platform-econotag-uip-rpl-override' and 'pull-requests/settings-for-all-targets' into bleeding-edge
Merge branch 'pull-requests/platform-avr-ravenusb-leds' into bleeding-edge
Revert "Cleaned up RF230BB, and refactored FRAME_RETRIES and CSMA_RETRIES"

This reverts commit b43dad00b0d598c7ee9f974b4a820a8fe5082d2e.

This change was reverted because it breaks the radio on
the `avr-raven` and `avr-ravenusb` platforms. The exact
cause of this regression has not yet been determined.

Conflicts:

	cpu/avr/radio/rf230bb/rf230bb.c
	platform/avr-ravenusb/contiki-conf.h
jackdaw: Move cdc_task and sicslow_ethernet over to ravenusbstick.

The "Jackdaw" firmware for the Atmel RZUSBStick could be very useful
on other platforms, but it's implementation is highly integrated into
the `avr-ravenusb` platform. This commit takes the first step toward
changing that, by moving the cdc_task and sicslow_ethernet code out
of the `avr-ravenusb` platform and into the `ravenusbstick` example.
platform/avr-ravenusb: Slight improvement to the RNG.
platform/avr-ravenusb: Added experimental mechanism to switch RDC at runtime.
bahhh
work-in-progress