CardReader: Change standby message.

The buffer that was used to calculate it did not contain the current salt.
Instead of creating a new buffer, we now use the sha1 block functions directly
and hash key and salt in two calls.

Additionally a ctx2hashhead function is added to convert only the first 4 bytes
of the hash instead of converting all 20 bytes and throwing 16 bytes away afterwards.

Display control error messages on Cardreader display
Reset Cardreader display after 4 seconds of idle to make sure the display is clean
when a new user inserts a card.
Detect a dead portal control and display an error message.

CardReader, Control: Change Polarity of Card-Detection / Reader-Power-Request pin to match the final hardware.

CardReader: Reduce APDU timeout to 600ms for the first answer byte and 300ms for the following bytes

Control: Add support for card key initialization/clearing
Control: Make debug output depend on #defines

Control: Wait for Cardreader LCD commands to be acked.
Control: Refactor state constant names.

reader power completely).
CardReader: Send reply when an LCD command is complete.

commin/i2c: Support bitrate changes (this seems to be broken, needs debugging)

Cardreader: Switch card power in software
Cardreader: Cleanup some dead code
Cardreader: Change IO Pins and Clockgen Timer to match new hardware.
Cardreader: Update LCD lib and set 4 bit mode pins.
Cardreader: Fix racecondition where serial interfaces bytes can get lost while processing an LCD command. The sender will now be notified when the commadn is complete.
Control: Support low battery shutdown override in new UPS.
Control: Support diabling keyslots
Control: Re-enable IDLE sleep mode.
Control: Change Cardreader power request pin polarity (high = power needed)
Control: Support RNG power software control (currently always on, to be changed).
Control: Update shell help command, to list all commands.

Main: Optimierungen.