eliminate util package in src/main

since util packages are a smell. most stuff moved to api package.
this is a postive advance now that we have a core package which
does not depend on api.

also accomplished by removing some unused code

not sure what to do about src/test/util, so just leaving it for now
Merge pull request #578 from NetLogo/slim-down-util-package

eliminate util package in src/main