OGR provider: deal with wkbUnknown25D (wkbUnknown | wkb25DBit)

This geometry type doesn't exist admitedly in the OGRwkbGeometryType
enumeration but a few OGR drivers can expose layers of this type.
Those layers should be dealt exactly like wkbUnknown layers, i.e.
QGIS should analyze the content to see if there are points, lines,
polygons and create derived layers.

Also report the geometry type of wkbGeometryCollection25D layers in
the U.I.
always also update qgis_en.ts in update_ts_files.sh run
[composer] Switch to alt key for resize and draw from center mode
[composer] Add some missing icons to menu items
Disable preview modes under OSX due to issues with QGraphicsEffects under OSX (refs #10761)
Disable color picker under OSX, due to limitations with QWidget::grabMouse on that platform
[FEATURE][composer] Allow specifying user stylesheets to apply to a HTML item's content
Initialize expression field buffer to NULL
Prevents crash, see
https://github.com/qgis/QGIS/pull/1494#issuecomment-50303556
Fix crash with maximumValue/minimumValue for virtual fields
[composer] Add function for getting a friendly display name for items
Request geometry when virtual field requires
Fix some warnings
[composer] Add api method for toggling visibility of composer items
Make table sortable. Fixes #10962
[composer] Support merged undo/redo commands for multiframe items
Follow up 3f0d0944
[composer] More improvements to item dispayName methods
Apply pull request #1502 provided by bstroebl: Add ntv2 entry for Thuringia
do not transform toString to quote values (NULL integer becomes 0 otherwise)
[FEATURE][composer] Implement an item tree panel for composer windows
(fix #4358). Allows for selection of items, hiding/showing items,
toggling lock status of items and double-clicking to edit item id.