Fixes to delay computing types on imported functions until they are used in the module being checked
Merge branch 'master' of github.com:cwi-swat/rascal
Modified the Rascal syntax rules describing keyword parameters

Reason: in the existing grammar KeywordArguments may contain Expressions
and these could therefore also occur in Patterns. This is problematic in
the compiler. The modified grammar avoids this.

Solution: KeywordArguments and KeywordArgument now have a type parameter
and can be used with Expression or Pattern:

syntax KeywordArguments[&T]
    = \default:  OptionalComma optionalComma {KeywordArgument[&T] ","}+
keywordArgumentList
    | none: ()
    ;
    
syntax KeywordArgument[&T] = \default: Name name "=" &T expression ;

Notes:

- ASTBuilder had to be changed to handle KeywordArguments and
KeywordArgument in a similar way as the non-terminal Mapping.

- All (modests) implications of this change have been fixed
Fixed all implications of change in Rascal grammar for keyword arguments
Merge branch 'master' of https://github.com/cwi-swat/rascal.git
Fixed error with leaking environments
Merge branch 'master' of https://github.com/cwi-swat/rascal.git
Fixed domain-related test
Updated test progress
Added support for slice assignment with operator; adapted to new
interface of type checker
Minor improvements
Test framework (interpreter) now adds test name to error message
Bug fix and improvements (thanks to Ferry Rietveld)
Give extra info for failed tests
Added test for LTE on lists -- will fail and needs fix soon.
Cranked up TRIES from 50 to 500: alas more tests fail now.
Corrected a test
Replaced some type parameters in tests by int.
Set TRIES to 500 for compiler's test framework as well
Updated test overview