Add support for conditionally-executed hooks.
Add macros for "modes" to common header.
Add initial implementation of linum-mode.
Fix face not understanding 'L' as a colour.
Make Transcript group highlighting less obtrusive.
Fix attribute handling of spaces in presence of RV or bright background.
Fix View not copying line meta correctly.
Fix linum-mode having an inverted sense of positive/negative.
Aggressively garbage collect before sleeping.