Configurable dev

After this merge lets stop using configurable_dev. Contributors should instead create a topic branches off of the `configurable` branch. If collaboration on a feature is needed we can create a common topic feature branch if necessary.

This pull request includes a [bugfix for I2C_READ_CONTINUOUSLY](https://github.com/firmata/arduino/commit/e28b07901aa4cae58f10200f9af0f64c940c3413) and a number of small formatting tweaks. The version has been bumped to 2.6.1.

I'm using the [sublime text astyle plugin](https://github.com/timonwong/SublimeAStyleFormatter) for formatting. I've only run it on Firmata.cpp, Firmata.h and Boards.h so far. I'll update formatting all files in an upcoming commit. The only change I've made in the astyle default options is changing spacing from 4 to 2 spaces (no tabs).