GROOVY-5632: Closure default params can cause BUG! exception in phase 'class generation'
GROOVY-5874: Closure shared variables are not rechecked in LHS of binary expressions
    * partial fix since there were two issues in one
    * test case for GROOVY-5893
Merge pull request #80 from andresteingress/GROOVY-5632

GROOVY-5632: Closure default params can cause BUG! exception in phase 'c...
merged
GROOVY-5886 Added ObservableSet plus testcase
Fix typos List -> Set
GROOVY-5074 Do not use ExecutorService to run code outside EDT, spawn a new Thread instead