Added ErrorContent.  Added FileSystemWatcher for auto-rebuild.
Fix: generating site in child dir of source site caused a kerfuffle.
Merge branch 'master' of https://github.com/mavnn/cantos
Quick hack in of a bit more code to make re-gen less agressive.
changed file system watching to throttle merged events using system reactive
Update Cantos/IO.fs
Merge branch 'master' of git://github.com/kolektiv/cantos

Conflicts:
	Cantos/IO.fs
Fix IO error if Pandoc not installed.