Refactor code to remove instanceof using double dispatch
Merge remote-tracking branch 'origin/master'
Refactor code to remove instanceof using double dispatch
Every file has a correct license again
Proposal: Remove the MapHelper (read on)

As suggested in #137 with cwi-swat/rascal (https://github.com/cwi-swat/rascal/pull/137), we can also do this with domainX, which is an existing library function.

I propose we use the standard library, and throw the MapHelper away.
Added separate data type for style attributes
Refactored widthStyleRule to intStyleRule
Added more styleAttr types
Missed some files

Wow, thanks GitHub for Windows, for not showing all modified files the
first time...
Finalized styleattrs for now
Added license to Color syntax
Error classes finished, now starting on the type checker
Merge branch 'master' of github.com:software-engineering-amsterdam/sea-of-ql
Added CSS compiler to QLS
Added (static) CSS compiler to QL, for consistency
Added range and stepsize to sliders
small changes
implement ide integration
small fixes
improve control flow