Merge pull request #1 from aodn/ui-extension-experimentation

UI For Configuring Layer Filters in GeoServer
Use FeatureTypeInfo for database agnostic layer property interrogation

SQL layers did not work correctly because there is no column information
for them.
Use the API correctly for a more robust way of locating a layer data directory
Make filter possible value reads database agnostic by using the API
Return to the layer listing page for filters when cancelling a layer's
filter form
Merge pull request #3 from aodn/form-cancel-button-behaviour

Return to the layer listing page for filters when cancelling a layer's filter form
Merge branch 'master' into ows-filters-service
Use helper method to get the file path
Remove unused methods and classes
Prevent empty value elements from being included in filters
Merge pull request #2 from aodn/ows-filters-service

OWS Layer Filters Service
Merge branch 'master' into edit-filter-column-type

Conflicts:
	src/main/java/au/org/emii/geoserver/extensions/filters/layer/data/io/PostgresSqlLayerPropertiesReader.java
Allow user to edit filter type

Required to override the default type as determined by GeoServer, in
particular handy for Geometry types