Minor version updates and code polishes

[seabamirum]

• Upgraded geotools, junit, maven-compiler-plugin and maven-surefire-plugin
• Deleted unused private methods
• Removed unnecessary else clauses that were followed by an if block with a return
• Added missing Override annotations
• Added static modifier to static methods when suggested by compiler
• In makeLayerInstance, replaced deprecated newInstance method with getDeclaredConstructor().newInstance()

[Andy2003]

@seabamirum Have you already signed the CLA?

[seabamirum]

Yes, I have signed the CLA. I think this branch is all properly synced up now..

[Andy2003]

@craigtaverner May you take a look at these changes?