bugfixes in Tuple#fld_join
removed unnecessary comment
removed 'label' attribute (left '__label' only) from class Sig
desabled atom renaming in alloy and updated the jar file
made java_to_ruby_arry more general so that it works with any java collection; a few other small optimizations
set renameAtoms alloy options to false; various other refactorings
updated test case for hamiltonian path