Adding dynamic USB power support

- Each scan module now has a current change callback which passes the available current as a parameter
- No longer attempts to use the max 500 mA immediately, starts with 100 mA then goes to 500 mA after enumeration
- If enumeration fails due to bMaxPower of 500 mA, then attempt again at 100 mA (might also be possible to go even lower to 20 mA in certain cases)
- Now working with the Apple Ipad (no over-power messages)
- Fixed Wake-up behaviour on Apple Ipad (and likely other iOS devices)
- More effecient set_feature/clear_feature handling (device handler)
- Initial power handling via Interconnect (still needs work to get it more dynamic)

Bootloader/dfu.desc.c

@@ -1,5 +1,5 @@
 // Originally Generated from MCHCK Toolkit
-/* Copyright (c) Jacob Alexander 2014-2015 <haata@kiibohd.com>
+/* Copyright (c) Jacob Alexander 2014-2016 <haata@kiibohd.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -38,7 +38,7 @@ static const struct usb_config_1 usb_config_1 = {
 		.bConfigurationValue = 1,
 		.iConfiguration = 0,
 		.one = 1,
-		.bMaxPower = 100
+		.bMaxPower = 50
 	},
 	.usb_function_0 = {
 		.iface = {