Added new section "lower.font": To avoid section overlap caused by the memory needs of the new characters, a new section has been introduced to store the font data behind the code and data sections. The handling is a little bit overengineered but was used to have the same look as the upper section, where a defined structure had to be rebuild to match the output of another compiler. moving the lower section behind the upper would save firmware space but result in the need of a new fontlib version.