Openlog compatible logging on serial port in MSP format

[sebastianherp]

A logfunction (very crude) to support logging on serial port via a connected (and modified = no command mode) OpenLog. It's just a preview. I'd like to make it more configurable and flexibel before even considered to be part of MultiWii (e.g. non blocking version with and "if" instead of while-loop, returning when buffer is too full)

Have fun ;-)

[wertarbyte]

Looks like there are a few changes in your patch that should /not/ be in there - e.g. your configuration. Please try extracting your actual logging code into a separate branch that diverges from upstream_branch and does not include any local changes - other people might have different copter setups :-)

[treymarc]

sending a long serial burst at each loop could affect cycletime in a negative way ,

[sebastianherp]

Arg ... ok it included the whole config.h ... instead of just one define in there ;-)

Cycle time is affected if over 36 bytes are sent, that is correct. I will include a possibility to use this without affecting cycle time at the cost of missing some cycles.