First function using the Java API of Opencv

* Opencv must be compiled first and the native library must be packed as a
jar file.
Functions to encode and view images

* Using seesaw for gui windows
* The functions are not complete
Encoding and conversion to bufferedimage are working
Functions to convert color spaces and thresholding
Function to calculate the histogram of an image
Function to calculate the concentration histogram
Fixed a bug in concentration-histogram function

* Some values could be nil before the fix, now just numbers are returned.