Fixed broken bit-shift in i2c_stop
Test Suite: always set -DNODE_CONF_ID when compiling nodes
INGA: Make nullrdc wait for autoack and generate fake ACKs in the radio driver
INGA Sensors: proper return values for configure calls

The Contiki sensor process calls the configure function of each configured sensor
on startup. The configure function should return 1 if the sensor has been configured
successfully and 0 otherwise.

This patch fixes the return value of the accelerometer, the pressure and the
virtual battery sensor.
Inga I2C Driver: Fixed infinitive retrying of i2c operations

I2C operations on the AVR controllers may fail if the I2C bus is
not ready (ATmega1284P data sheet page 219). This can for example happen,
if you connect external I2C slaves that are not powered all the time. Retrying
infinitively in those situations is usually not a good idea.

This patch adds a retry limit of 800 tries to each repeated I2C operation
to avoid nodes to hang forever.
core/net/uip-nd6.c: addded missing whitespaces for debugging outputs
core/lib/settings.h: fixed calls to settings_get()
Makefile.include: Setting RELSTR based on git tags requires to be in
the contiki directory
platform/inga/contiki-inga-main.c: New boot screen and updated EUI64
setting
platform/inga/contiki-inga-main.c: Fixed router periodic prints
contiki-inga-main.c: readded setting of rime address for uip