spelling
fix overflowing BNF rule
more consistent BNF
fix #885, don't allow => for values annotated variable
fix #905 object declarations leaking self refs + update spec
refix #905
fix #900
minor
test for bug
fix bug in definite return analysis for continue
add unsupported warning to address #896
Squash bogus unused warning on setter for #889
fix #887
rollback part of #887
completely disallow recursive attribute defs for #887
update typechecker for new def of Category
update tests for lang module changes
subtraction moved up to Invertable
test for typing of in operator
fix bug refining overloaded method of generic class 
spotted by Stephane Galles