Refs #2320: Adds displayName property to DataCategory.
Merge branch 'release/3.1.0' into develop
Updated version to 3.2.0-SNAPSHOT

Change-Id: I09ee5189954b092aa55590a8e8186b8d1b24a694
Revert default gravity to 100 and change documentation.  Refs #2296
JavaDoc change: Added warning about URLConnection
Refs #2137: Creates the following events/listeners: SessionAboutToBeLoaded, SessionLoadCancelled and SessionSaveCancelled.
Javadoc change: modified documentation about CyTable primary key types
Merge branch 'develop' of https://github.com/cytoscape/cytoscape-api into develop
Refs #2387 - replaced buggy private getExtention method with FilenameUtils. getExtention (see its docs; never gets null, never gets log “extension” containing slashes, etc.)
Added the getExtension (BasicCyFileFilter api) method back.
Commons-IO version number has been fixed to the one provided by features.xml.
References #2387: Inlined code from commons-io so we can avoid including it as a dependency.

Change-Id: I0c30a7329362779b99241b22ff23ef86afe2bec4
Modify comments to indicate correct package

Change-Id: I033452c7426364b40614829e89fab5d8ba508ac2
References #1928: Renamed "Attribute" to "Column" for consistency with rest of core

Change-Id: Ia51edc45487109fb28ae2484a611cf11581a83d9
Refs #2466: Adds clearVisualProperties method to View interface
References #2315: Updated javadoc based on feedback from Kei.

Change-Id: Iac3599cead82915ed42da7fef0a6bb250299d25b
Tunables with equal gravity now retain default ordering with the
addition of equals case to TunableGravityOrderer.
Refs #2530: Adds getNetworkViewRenderer(String) method to CyApplicationManager.
Minor fix to AbstractNetworkCollectionTaskFactory.isReady--also checks if network list is empty.
Expose and document all map parameters.  Refs #2525