android-api: Make Services.match() compatible with version 0.12.x

Since the application and management API has not been changed since version 0.12,
there is no need for an additional version. Thus, we define 0 as the required version.
android-api: Add old-style API checks to Services.match() method
android-daemon: Disable hardware requirements
android-daemon: Manifest clean-up
recipes: Disable DHT by default on OpenWrt
tools: Hashing in dtnoutbox
daemon: Generate DH params for key-exchange only if enabled

Since the generation of DH params might be quite slow. The default bits are reduced to 1024 and the automatic generation is only enabled if the configuration option 'generate_dh_params' is set to 'yes'.
recipes: Add 'generate_dh_params' to daemon UCI configuration
daemon: Do not always generate an error message bundle in key-exchange
daemon: Key-exchange message formatting
android-daemon: Key-exchange UI redesign and fixes

Merged KeyInformationActivity and ProtocolSelectionActivity
Use ShowcaseView library to point to action items
NFC key-exchange now accessible from local key information activity
Show QR codes scanning option only if there is a key
DH protocol disabled
Scale QR code with screen resolution
Re-design of UI elements
Fixed exchange work-flow
android-daemon: Use Mode.SRC_IN instead of Mode.MULTIPLY for colored icons
android-daemon: Use color filter instead of colored background for symbol icons