XD-1819 Runtime executables share jars in xd\lib

This reduces the size of XD dist zip from 390.4MB (M7)  to 252.3MB -- about 25MB due to discontinuing support for older Hadoop distros (XD-1854 applied after rebase).  This is accomplished by configuring xd-shell, hsqldb-server, and gemfire-server, to share jars already in xd/lib.  The build is modified to exclude such jars from the distribution and the runtime scripts are modified to add xd/lib  to the classpath.  I have started up and smoke tested these runtimes on Mac and Windows XD.   

Further space savings can be achieved by normalizing duplicate jars in the module lib directories. However there is some major work on the Module Registry proposed for 1.x, so this should be addressed then.  
I think the trade-off we take here to avoid duplicate libs in hsqldb and xd\lib is to include all the third party libraries from xd/lib along with spring-xd-batch* jar in the classpath to start the hsqldb-server. I believe this won't conflict with any of the new library that might get added either in spring-xd-batch and xd\lib.