Overall: lowercased CMake stuff.
Overall: remove CMake-language block-end command args.
Merge branch 'master' of github.com:0xd34df00d/leechcraft
Interfaces: add FromKnown_ to CustomTag struct.
Blogique Metida: use blockquote instead of hr for lj-cut.
LHTR: support FromKnown_ for custom tags.
LHTR: expand custom tags on inline insertion.
Interfaces: return bool from CustomTag::FromKnown_.

We need to indicate conversion failure or success.
Blogique Metida: fill in FromKnown_.
LHTR: gracefully fallback to __original__ if FromKnown_ failed.