Full Eclipse support without the need for Buildr.

This commit adds the buildr generated .classpath and .project files.
Normally, I wouldn't place generated files into version control.
However, I added these in the interests of ensuring anybody can build this.
The libs folder reflects the maven repository directory organization.
Anyone following the README can now build and run Logisim in Eclipse.
Well, in theory.
Tested existing Nulls class, deprecated it.
Deprecated GifEncoder.
Merge branch 'build' into refactor
Silly me, it turns out Nulls isn't even used elsewhere.
Capitalize apparently not used.
Modified StringGetter in preparation for deprecation.
Deprecated StringGetter.
Removed GifEncoder, as it is not necessary anymore.
Merge branch 'build' into eclipse
Got rid of ArraySet, since HashSet seems to work.
Include Apache Commons as a dependency.

This commit updates the build script, .classpath, and and the license.
Apache Commons is not compatible with GPLv2, but with GPLv3.
Merge branch 'build' into refactor
Merge branch 'refactor' into eclipse
Removed mention of Gif Encoder from documentation.
Merge branch 'gifEncoder' into refactor
Merge branch 'build' into refactor
Merge branch 'refactor' into eclipse
Updated README to explain the extra build dependencies.
Minor tweak to getLocale()