Fix bug in GTMURLBuilder that doesn't handle url path with escaped characters. E.g. http://www.google.com/path%3AA/path%3AB would become http://www.google.com/path%3AA/path%3AB/path:A/path:B

DELTA=20  (14 added, 3 deleted, 3 changed)

git-svn-id: http://google-toolbox-for-mac.googlecode.com/svn/trunk@612 7dc7ac4e-7543-0410-b95c-c1676fc8e2a3