Fix warning messages, generated by Maven (v3), during build.

* Added missing version numbers for build plugins and dependancies.
* Removed duplicate dependancies.
* Updated obsolete groupId.
* Added minor formatting changes.
Properly encode Not filters
Fixed longstanding typo
Updated contributor guide to reflect small patch policy
Merge pull request #212 from bencaradocdavies/patch-policy

Updated contributor guide to reflect small-patch policy
Merge pull request #211 from dustinparker/notfilter-encoding

[GEOT-4488] Properly encode Not filters
GEOT-4489 JDBCDataStore - incorrect extent calculation in case of multiple geometry attributes
GEOT-4490 DB2 extent calculation performance for large data sets is not acceptable
having fun with diagrams

Signed-off-by: Jody Garnett <jody.garnett@gmail.com>
Correct SOSNOKILL License to BSD License

Signed-off-by: Jody Garnett <jody.garnett@gmail.com>
Adding some missing DB2 tests
[GEOT-4491] Hints.getDefault() implementation hampers scalability
[GEOT-4492] DataUtilities.fileToURL checks system variable fo OS every time, hampering scalability
[GEOT-4493] CRS repeated checks for axis flipping system variable hampers scalability
GEOT-4494,Improve ImagePyramidFormat accepts checks
Merge pull request #214 from geosolutions-it/master-pyramid

GEOT-4494,Improve ImagePyramidFormat accepts checks
Allow the transforming wrappers to work off an empty feature source/store
Upgrade the build plugins to the latest version.

The report plugins were not modified.

* The configuration of the surefire plugin in the imagemosaic/pom.xml was altered to conform to the requirements of the latest pluigin.
* Inserted some missing groupIds.
* Inserted some missing versions.
* Minor formatting changes.
* Removed some obsolete comments.
Fix license headers
Correct obvious bug in SimpleFeatureImpl.setValue.