Only build NFC if libnfc-nxp headers are available.
Merge pull request #113 from amccarthy/nfc-conditional-build

Only build NFC if libnfc-nxp headers are available.
properties: separate properties in another library

So it can be used without necessarily depending on libhybris.

Signed-off-by: Ricardo Salveti de Araujo <ricardo.salveti@canonical.com>
properties: add support to get/set property via the property service

The property service is running inside the android init daemon and
creates a socket in /dev/socket/property_service which we can use
for setting properties (getting is done via an extra android patch
to add 'get' and 'list' support in the property service).

Additional patches for the Android init system can be found at
http://people.canonical.com/~rsalveti/properties/

Based on a similar patch by Simon Busch <morphis@gravedo.de>.

Signed-off-by: Ricardo Salveti de Araujo <ricardo.salveti@canonical.com>