nanohttpd antfile modified

Ant file now takes property values for the nanohttpd directory location,
as well as the core and webserver source within.  Additionally, the
created jars now include the .java files alongside the .class.
Jars recompiled
Empty build directory placeholder file added
Rearranged the main Spritely class

Spritely.java is now located in the net.synapsehaven.sprite package.
The Plugins class is now also its own separate file.