bug fixes on pi
added i2c_pid and heading to state when created
rebase and merge from bug fixes on pi
correct errors using I2c
fixed errors
corrected error with handle_calls
correct function heads for handle_call s
Merge branch 'master' of git://192.168.1.106:9418/hmc5883l

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added terminate to headingserve to be implemented later
added documentation for HMC5883L