Replace gwt.svnrev with gwt.gitrev.

Change-Id: I3f28322bd6c127b5cfff968c178fa27d001679b8
Add newer versions of commons and httpcomponents libraries

I did some investigation and I picked versions of libraries which should
be most compatibile without code change.

I'm checking them here, since i don't have access to svn with tools used
to build gwt
Don't embed commons, httpcomponents into gwt-dev.jar

Although we compile with newer jars, we dont want to force one specyfic
version of components.

People using compiled gwt sdk will have make extra effort to include those
jars in their classpath.
Include newer jars exluded from gwt-dev.jar into final dist zip