Update README.md
Update README.md

added www. to download for MS Windows link because site of "antlr.org" doesn't work but "www.antlr.org" does work
Merge pull request #468 from whitten/patch-1

Update README.md
Update README.md
Increment current while adding a collection to IntegerList (fixes #474)
Merge pull request #475 from sharwell/fix-474

Increment current while adding a collection to IntegerList (fixes #474)