error handling in the I2C communication

added a class I2CComm that handles the whole communication with the I2C
bus and sensors, but let the dev handle errors, error types, and do
something with it (more specifically, would be used within the SAT_*
sensor libs, coming in next commit).
corrected anomalies in the management of addresses

the address is read from EEPROM, and the assvAddress is set 0x04
(I2C_ADD_ASSV_1). in the previous version, the local address of the node
used for Wire.begin was 0x04.
refactoring to integrate I2CComm

refactored the SAT_Lum, SAT_Mag and SAT_Temp to use I2CComm class the
management of communications through I2C. This helps to make the multple
calls to Wire.begin() converge into a single place, and keep a
consistant local address of the node (that should be decided in
I2CComm).
inclusion IDE-compatible

"rollback" from relative path inclusion in SAT_Mag, SAT_Lum, SAT_Temp
and I2CComm.
still working with the IDE, but needs to include all the dependencies
from one sketch to compile.
All examples are compiling from the IDE.
changes suggested

changes suggested by bordicon on the last commits (I2CComm).
implementation of SAT_Accel / I2C

implementation of the SAT_Accel library, small modifications from the
code of the "ADXL345 Driver for Arduino", adaptation for I2CComm,
examples validates with a real ADXL354 and working
alignment of SAT_Geiger, SAT_Infratherm with I2C

- modification of I2CComm to integrate specificities of Geiger and
InfraTherm
- modification of these libs to use I2CComm
- minor revision of SAT_Accel to specify types
adding SAT_Gyro

add support for the ITG-3200 3-axis gyroscope in the sdk, based on
I2CComm communication.
examples tested on the real sensor.
adding function in I2CComm

added a getAddress() function to be able to test it.
OBCL + AppStorage update

- proposition or an harmonization of OBCL with the rest via I2CComm
- modification of I2CComm on flush functions (and propagation to geiger
example)
sync with the last master pull request
Revert "sync with the last master pull request"

This reverts commit 243f6784c96f9fe5582492ddf058ea045320b7ac.
Merge branch 'master' into debug
fusion I2CComm+OnboardCommLayer

- fusion of the I2CComm library with the OnboardCommLayer class to
regroup functions related to I2C communication.
- nanosat_message and I2C_add integrated into OnboardCommLayer directory
- alignment of all sensor libraries with this update, example sketches
compiling in Arduino IDE.
Merge pull request #5 from jfomhover/debug

Bring ArdusatSDK in line with JF's Improvements - FIGS