repackage UIMA-AS to work as an add-on to base UIMA

Change the UIMA-AS "binary" packaging to be an "add-on" to base UIMA.

1. remove uima base jars from uima-as bin packaging
2. change instructions for installing uima-as to unzipping/taring over base uima level
3. update docs to reflect this packaging.
4. verify that javadocs generate, and that docs say there are 2 javadocs sets - one for base UIMA and one for uima-as addon
5. verify that uima-as startup checks for compatible level of uima base (today this means equal level)
6. verify that the binary examples (in the UIMA_HOME/examples directory) is the proper merge of base and UIMA-AS
7. verify that the scripts work