class system: compat fixes
test framework: use chai with mocha
codeeditor: trying to pin down serialization issues
lively.lang.VM: accept sourceURL as eval option to improve stack readability
lively.lang.VM/JS tools: use sourceURL when saving or for doits
ide: fix item expansion in inspector ofr "unnamed" items"
scb: also using sourceURL for evals. TODO: switch to lively.lang.VM interface for evals
lively class refactoring: compat fixes