Various things are working with the new system
Phase #2: Custom commands per mode, eliminate built-ins
Eliminated ctags and check tools
Eliminated all tools, refactored language JSON format to be much
cleaner. Added extra "preview" event, renamed "textchange" event to
"change".
Renamed some arguments, passing on options again
Fixes #21 and cleans up various other aspects of the refactor.
Fixes #19 adds watcher support to syncfs.
Slight tweak in error handling
Little cleanup, updated the doc a bit