Add doxygen configuration
Change comment to the Doxygen style
Changes to the output language
Enable dot\graphviz
Tune the Doxygen configurations
Add mainpage
Tune doxygen configs
Switch off UML
Format comments
Add rime logo
Use rime logo
Increase the DOT_GRAPH_MAX_NODES
Revert "Add mainpage"

This reverts commit 73029111bc443bcb87355feb3294670c09dbe628.
doc/Doxygen: use README as main page.
Merge branch 'doxygen' into develop