[GEOT-4802] Creation of two new processes called BandMerge and BandSelect.

Please look at the following JIRA: http://jira.codehaus.org/browse/GEOT-4802.

Note that the pull request also adds the "it.geosolutions.jaiext.roiaware" string as JAI Authority inside the gt-referencing module. This has been done in order to accept my new JAI operations.