Introduce Echo3 dependencies as Git Submodule.

Conflicts:
	ant.properties
Upgrade dependencies to include JUnit & Co.
Update submodule pointer to latest, cleanified commit.
Merge branch 'feature/build-lib-gitsubmodule' of github.com:exxcellent/echo3

This introduces a Git submodule reference which provides all required
3rd party libraries to compile Echo and adjusts the default build
properties accordingly.

Resolved conflicts in ant.properties and did some minor corrections.
Upgrade to JDK 1.5, as previously merged BoxShadow feature introduced an enum.