add uglify-js 2.2.5 to the package.json dependency list
replaced all prettyPrintJson() calls with 3 parameter form of JSON.stringify()
remove unused variables
AST parsing, builtins handling, and compression/mangling have been converted to use uglify-js 2
removed old requires
renaming the mangle.s AST parser module to compress.js to be more in line with uglify-js 2 naming conventions
squeeze.js AST module no longer necessary, now handled in compress.js