Hides download button and adds message when download estimator calculates Zero bytes
Test fixes. Changes to code to facilitate the tests
Clear all button re-titled and tooltipped
Collection in the details panel is now hidden when empty
Fix tests
Fixes code broken by test changes
Fixes code broken by test changes. Take2
Review changes
Merge pull request #1267 from aodn/issue-1221

Issue 1221
Removed unused code.
Fix for #1215 - each layer now has its own 'DetailsTabPanel' (rather than being shared).
Style panel initialised with layer.
InfoTab is now initialised with layer.
Renamed 'initWithSelectedLayer' to 'initWithLayer' for consistency.
SubsetTab and FilterGroupPanel are now initialised with a layer.
NcWmsPanel is now initialised with a layer.
Merge pull request #1261 from aodn/issue-1227

Hides download button and adds message
Removing unused i18n values
Deleted unecessary show/hide code in DetailsPanel.
Merge pull request #1270 from aodn/removing_unused_i18n_values

Removing unused i18n values
Removed remnants of 'handleLayer' related code.
InfoPanel now extends Ext.form.Label, since it is just some HTML (and calls like `this.body.update` were causing issues when the panel had now been rendered).