Delimited text GUI tidy up.  Renamed useWatcher option to watchFile
Minor gui fix
Delimited text plugin moved to core
Fix merge conflict
Fixing line spacing in <pre> section of delimited text context help
Merge pull request #591 from ccrook/delimited_text_to_core

Delimited text to core
Disallow changing of map layer registry directly
QgsMapLayerRegistry::mapLayers() returned reference is now const
Fix generation of empty layer/style entries
Use a cosmetic pen for snap lines to prevent lines scaling (fix #7524)
Fix wmsserver: Do not manipulate maplayerregistry directly
[Fix #7806] Be more verbose in "invalid layer" dialog
Small fixes
 * Fix minor memory leak in attribute dialog
 * Safety check in dual view
[attrtable] Make sure editor widget background is not transparent
Fix #7835, opening WMS layer properties causes crash
Update labeling gui and add expression support as data defined value

- Add QgsDataDefined class
- Add QgsDataDefinedButton class
- Add data defined Python support
- Add standalone SVG selector dialog to QgsSvgSelectorWidget class

- Fix for #4607, show only pertinent fields when setting a data defined value
- Fix for #5048 and #5049, data defined settings are literally used
- Fix for #5726, number formatting does not work for expressions
- Fix for #7755, using bufferSize to enable/disable label buffer is confusing
- Fix for #7779, labels do not register in label collision engine; and for #4719, inactive options in labeling dialog
- Prepare label text's expression upfront when preparing layer; makes rendering much faster
- Change name of 'feature obstacles' to appropriate terminology