Switched from ant to maven:

Maven is used to build the plugin. I had to change the folder structure to meet the maven requirements.

I had to change some small code pieces to be compatible to Java 1.6.0_24, which is distributed with Fiji.
Merge pull request #6 from EFTEMj/toMaven

Switched from ant to maven:
This leads to a new folder structure.
I had to remove some Java 7 code to be compatible to Fiji that uses Java 6.