Add PluginLoader, a super simple plugin framework that allow for dynamically
loading JAR files after startup and searching for plugins that implement a given
abstract class.
Add a unit test with dummy plugin and implementations. The makefile will compile
a plugin jar that the unit test will load at runtime and check for implementations

Signed-off-by: unknown <clarsen@euphoriaaudio.com>
Signed-off-by: Chris Larsen <clarsen@euphoriaaudio.com>