Fix ctkDICOMQueryRetrieveWidgetPlugin widget name

Closes #287
Ensure languageCombox consider qm files

Closes #291
Merge branch '291-ensure-language-comboxbox-consider-qm-files'

* 291-ensure-language-comboxbox-consider-qm-files:
  Ensure languageCombox consider qm files
Keep ctkVTKConnection slot as const char*

Converting from char* to QString is significantly time consuming.
Merge branch 'ctkVTKConnection-speed-up'

* ctkVTKConnection-speed-up:
  Keep ctkVTKConnection slot as const char*
Put tag caching in an sqlite transaction for efficiency

Since we may have a long list of tags to cache, put them all in
one transaction to minimize sqlite overhead.
Merge branch 'cache-tags-in-transaction'

* cache-tags-in-transaction:
  Put tag caching in an sqlite transaction for efficiency
Improve sql safety and performance

Use mutex locks to protect all exec calls in case they come from
different threads.

Also add begin and end transaction calls when inserting to the database
in hopes of improving performance.
Remove threading to avoid crashes (see #292)

Seems that sql and threading is not a good idea
after all.
Update the progress dialog as files are indexed

The dialog will now support cancel and resize even though
the indexing is not being done in a different thread.
Only use sql transactions for tag cache

Since transactions cannot nest.
Remove threading code from dicom database and indexer

See discussion at #292.

Pending a re-implementation, remove thread support from the
ctkDICOMDatabase code.  Since the ctkDICOMDatabase internally
manages the database connection, the threading code should make
multiple instances of the database (one per thread) rather than
calling the same instance from multiple threads.  Because of this
there is no reason to have a mutex internal to the class.
Related call, methods, and member variables have been removed.
Merge pull request #288 from gaoyi/287-ctkDICOMQueryRetrieveWidgetPlugin-name-mismatch

Fix ctkDICOMQueryRetrieveWidgetPlugin widget name
Update test to reflect current behavior of database/cache
Merge branch '292-non-threaded-inserts'

* 292-non-threaded-inserts:
  Update test to reflect current behavior of database/cache
  Remove threading code from dicom database and indexer
  Only use sql transactions for tag cache
  Update the progress dialog as files are indexed
  Remove threading to avoid crashes (see #292)
  Improve sql safety and performance
Don't delete ctkProxyStyle when widget is destroyed

There is no way to reassign the proxys of all the base styles to a
different proxy.

This prevents a crash when loading the ctkWidgetsPlugin into the designer.
Closes #289
Merge branch '289-designer-plugin-crah'

* 289-designer-plugin-crah:
  Don't delete ctkProxyStyle when widget is destroyed
vtLightBoxRendererManager now supports VTK 6

Issue #290
Merge branch '290-vtk-6.0-support'

* 290-vtk-6.0-support:
  vtLightBoxRendererManager now supports VTK 6
Remove compile warnings - Closes #293