Fix build warnings for shadow default assignment operator

These were revealed by paraview dashboard
Merge pull request #339 from gcasey/warnings-fix

Fix build warnings for shadow and default assignment operator.
See http://open.cdash.org/viewBuildError.php?type=1&buildid=2933423
Fix ctkColorDialogTest2 time out

ctkColorDialog::getColor() already pops up the dialog, there is no need to
exec the app. It would otherwise hang there as no window is shown.
Remove ctkColorDialog warnings when not using nameSignal

If not provided, the nameSignal property is const char* 0. It is a valid
QVariant, but it can't be used to connect/disconnect.
Merge branch 'ctkcolordialogtest2-timeout'

* ctkcolordialogtest2-timeout:
  Remove ctkColorDialog warnings when not using nameSignal
  Fix ctkColorDialogTest2 time out
Use Q_DISABLE_COPY Qt macro everywhere in CTK
Merge branch 'use-q_disable_copy-macro'

* use-q_disable_copy-macro:
  Use Q_DISABLE_COPY Qt macro everywhere in CTK
Cross reference ctkPathLineEdit, ctkDirectoryButton and ctkPathListWidget
Merge branch 'ctkdirectorybutton-see-also'

* ctkdirectorybutton-see-also:
  Cross reference ctkPathLineEdit, ctkDirectoryButton and ctkPathListWidget
CLI module .xsd: the 'channel' element is not special

don't make the optionality of the channel element stand out;
the other optional elements do not have maxOccurs=1 & a comment
Merge pull request #344 from hmeine/master

don't make the optionality of the channel element stand out in ctkCmdLineModule.xsd
Fix CMake unused variable warnings

Introduced by commit 8c9868f5, the variables "ExternalProjectsContrib_DIR"
and "PluginsContrib_DIR" where unconditionally passed down when
configuring CTK inner project.

This commit avoid the "unused variable" warnings by checking the value
of "CTK_USE_CONTRIBUTED_PLUGINS" variable before passing the variables.
Merge pull request #345 from jcfr/fix-unused-variable-warnings

Fix CMake unused variable warnings
Rename ctkSpinBox to ctkDoubleSpinBox
Merge branch 'rename-ctkspinbox-into-ctkdoublespinbox'

* rename-ctkspinbox-into-ctkdoublespinbox:
  Rename ctkSpinBox to ctkDoubleSpinBox
Merge branch 'slider-inverted-properties'

* slider-inverted-properties:
  invertedAppearance and invertedControls properties for ctkDoubleSlider, ctkDoubleSpinBox and ctkSliderWidget

Conflicts:
  ctkDoubleSpinBox.h
  ctkDoubleSpinBox.cpp
Fix timeout in ctkPathListWidgetWithButtonsTest with Qt 4.6.3

The thread was deleted and the singleshot was not executed before the
dialog was closed.
Closes #340
Merge branch '340-ctkpathlistwidgetwithbuttonstester-timeout'

* 340-ctkpathlistwidgetwithbuttonstester-timeout:
  Fix timeout in ctkPathListWidgetWithButtonsTest with Qt 4.6.3
Add ctkComboBox::ScrollEffect
Merge branch 'ctkcombobox-no-scroll'

* ctkcombobox-no-scroll:
  Add ctkComboBox::ScrollEffect