MPL115A2 driver

 add (very simplistic, blocking delays etc.) a driver for the MPL115A2
barometric pressure and temperature sensor. Returns Pressure in pascal and
Temperature in milli-celsius.
add L3G4200d driver code

 driver for the STMicro L3G4200d gyroscope. Non-configurable, read at maximum
supported rate. Returns rotation speed in degrees per second on three axes and
temperature in degree celsius.
VCNL4000 sensor driver

 add the vcnl4000 ir-distance and ambient light sensor driver. Currently there
seems to be a problem with the jnode hardware regarding ir-distance measurement,
measuring ambient light-levels does work.
changes from lightlevel-sensor.h
add lsm303dlm sensor driver

default sampling rates, returns accelerometer and compass readings.
add jnode platform implementation
small cosmetic change on the vcnl4000
shell sense returns if sensor not found, i2c fixup
remove callback support in ieee802.c

 was not used anyhow
hopefully gdb support on jn5148
fix non-debug builds (typo)
remove i2c_init

 and let i2c() handle i2c unit power-up and -down
irq-based i2c and uart operation

 because of quirks with the i2c-hardware on jennic modules, this has to be done
in a process (it is impossible to control the i2c-hardware from the i2c-irq)

 change the sensors accordingly. Should be read by waiting for the sensor_event.

 uart operation is now irq-based. BIG WARNING: reception is currently not
working.
disable uart reception for now!
change printf behaviour

 every printf call will be redirected to uart0 now!! default baudrate is 38400.

 shell-sense command gives some statistics now too
add sdcard (SPI) support with PetitFatFS layer
possibly fix sht sensor
support for retrieving timestamp on rx'd packets

 Not using the packetbuf attribute api for that since it only supports 16-bit
attributes (not enough for wall clock timestamp).

 Timestamp can be retrieved with ieee_get_last_timestamp(), returns hrclock_t
timestamp. Needs to be activated with JENNIC_CONF_TIMESYNC, to avoid unneccesary
overhead for applications not using it.
Merge branch 'master' of github.com:pscholl/contiki-jn51xx
fix uart0 rx