initial import in git repository

added git attributes
added readme for GitHub
removed legacy code (supporting Arduino pre-1.0 versions)

patched soft-serial libraries are no more required
added some pictures for documentation
added thumbnails to readme
updated doxygen documentation

added pictures and updated library version
updated doxygen configuration
added microphone distance settings
updated library keywords
updated readme with license info
fixed bridge detection issues on some systems

some Arduino core libraries do not seem to handle "flush" reliably, leading to lost characters
added support for wake-up status
added tests for sleep mode and microphone distance settings
removed support for old Arduino versions (pre-1.0)
removed support for old Arduino versions (pre-1.0)

also removed old bridge mode using AVR EEPROM
fixed compilation on ATmega168

changed all string literals to use PROGMEM and save RAM space
fixed a typo in the doxygen comments