Implement interrupt exception

The thing about an interruption is that it will not be caught even if
RethrowErrors is false.
Implement break and continue tags
Merge remote-tracking branch 'rdumont/feature/break-and-continue-tags'

Conflicts:
	src/DotLiquid/Liquid.cs
	src/DotLiquid/TemplateConfiguration.cs
	src/DotLiquid/Tags/For.cs