Add test and doc targets to Ant build file

I've added three targets to the Ant build file
1. "build-test" which builds all tests in test/* into build/classes/
2. "test" which invokes a JUnit target on anything called *TestCase
3. "doc" which simply builds API docs to docs/

I've been as consistent with whitespace as I can be, but I'll note that the spacing in build.xml seems to mix tabs and spaces, whereas in the style in .java files doesn't mix spaces and tabs.