initial implementation of FirmConfigSource
ConfigSource: Implement line/stream parsing in base class to reduce code duplication
FileConfigSource: use base class parsing routines
FirmConfigSource: use base class methods
Makefile: keep default configuration in flash, do not load into ram at runtime
Merge remote-tracking branch 'upstream/edge' into firmconfig
Merge branch 'edge' into local-firmconfig
Merge remote-tracking branch 'origin/edge' into local-firmconfig
Merge remote-tracking branch 'upstream/edge' into firmconfig
Merge pull request #142 from arthurwolf/firmconfig

initial implementation of FirmConfigSource