Update build tooling (WARNING: Rearranges source tree)

[ferdnyc]

As requested by @parg in #5, this PR contains an updated build.xml which can (when copies of swt.jar and BiglyBT.jar are made available to it) successfully compile an rssfeed_version.jar and package it into an rssfeed_version.zip for distribution.

# To build the jar file
$ ant jar
# To build the zip file
$ ant dist

In the course of doing this, I rearranged some of the source tree (moving the resources files into a top-level subdirectory, for instance), in ways that I'm worried are going to mess up @parg's own, existing build scripting.

So I guess... be sure to test before merging? 😁 LMK if any changes are needed, I'll be happy to fix what I broke.

[parg]

plugin.properties references the package location of the message text files...

View.java and Help.java also reference the location of the icons and the .stf files