update MetaSearch to 0.3.1
remove code
merge back ef0e7d09168d43b0529a1f819108a4741c7e9e75
[FEATURE] Visibility groups of map layers in layer tree

New toolbar button allows quick changes between the groups of layers that should be visible.
Also features a simple way for management of the groups (add/remove)
[FEATURE] Access to visibility groups in map composer
fix warnings
postgres provider: don't warn, when queries return 'numeric' constants
Fix Mac build
Fix crash when trying to edit color ramp with black start/end colors
Visibility groups: also record visibility states of renderer categories (legend nodes) into groups

Visibility of a layer is not stored within the map layer, but visibility
of renderer categories (which turn into legend nodes) is stored inside renderer and
that one in turn inside map layer. This fact may result in surprising behavior
when change of visibility group for a composer map will affect other composer maps (and main canvas).
The only way to overcome the problem would be to have the possibility to use multiple renderers with one layer.
[FEATURE] Toolbar for layer tree specific actions
Fix #11143 (remove visibility groups after removal of a layer)
Keep a bit of spacing in layer tree dock widget
If layer is in editing mode, show the pencil icon instead of embedded legend icon
Respect the overridden layer name in composer legend also in rendered legend
Fix #11126 (Make up/down buttons work also for layer tree nodes)
Fix QgsLayerTreeModel naming conventions and update Python bindings

I was using a mixture of terms 'symbology items' and 'legend nodes' for the same thing which was confusing
Fix potential crash when adding a group
Merge pull request #1575 from geopython/MetaSearch-0.3.1

Meta search 0.3.1