[python] style, partial python3 compat

- pep8: 4 spaces
- use 'in' instead of has_key for checking dicts
- some fixes for settingsapp
[python] fix settingsapp: use generated var/<acname>/settings.xml
[python] filter returns an iterator in python3, make sure it stays a list
[python] cleanly shutdown messages_app
[python] more cleanup

- pep8: 4spaces indentation
- print_funtion
- use 'in' instead of has_key for dicts
- log stuff not tested...
[python] fix realtimeplotapp

realtimeplotapp calls Stop() on IvyMessagesInterface and expects it to only unbind.
Add an extra Shudown method for messagesapp that also stops Ivy.
[python] towards python3 compat: division, map
[GUIDANCE] abs(c_route) and abs(s_route) instead of abs(route) in north and east route components calculation
[logalizer][fix] add pcre lib to plotprofile, weird...

Very weird stuff: works here on several Ubuntu 12.04 machines without explictly adding -lpcre
For Pranay it only works with explicitly adding it gcc ... --verbose outputs _exactly_ the same stuff as on my machine, but he gets:
/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../lib/libglibivy.a(ivybind.o):function IvyBindingCompile: error: undefined reference to 'pcre_compile'
/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../lib/libglibivy.a(ivybind.o):function IvyBindingCompile: error: undefined reference to 'pcre_study'
/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../lib/libglibivy.a(ivybind.o):function IvyBindingCompile: error: undefined reference to 'pcre_fullinfo'
/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../lib/libglibivy.a(ivybind.o):function IvyBindingFree: error: undefined reference to 'pcre_free'
/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../lib/libglibivy.a(ivybind.o):function IvyBindingFree: error: undefined reference to 'pcre_free'
/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../lib/libglibivy.a(ivybind.o):function IvyBindingExec: error: undefined reference to 'pcre_exec'
collect2: ld returned 1 exit status
[dox] fix typos: rates are in rad/s
[lpc21][imu] aspirin_i2c defaults to i2c0, configurable via ASPIRIN_I2C_DEV
[makefile][imu] configurable ASPIRIN_I2C_DEV
[conf] remove unused MAG_[XY|XZ|YZ]_SENS defines
[ext] update luftboot submodule

PREFIX now needs the trailing dash, so /foo/bar/arm-none-eabi-
[ext] PREFIX without trailing dash again, like in libopencm3
[imu] aspirin: print SPI/I2C devices
[config] consistent foo_I2C_DEV and PRINT_CONFIG
[lpc21][i2c] clear naming for i2c channel
[mcu] add missing include for INFO macro
[lpc21][i2c] trying to fix disabling/re-enabling of i2c interrupts