Add ctkDoubleSpinBox::DecimalsByKey, DecimalsByValue and ReplaceDecimals
Expose ctkDoubleSpinBox::DecimalsOption to other widgets
Fix ctkSliderWidget assert when changing decimals with DecimalsByValue

By blocking signals in ctkSliderWidget::changeValue, the change of decimals
(because of ctkDoubleSpinBox::DecimalsByValue) is not catched by
ctkSliderWidget and not propagated to the slider which causes a discrepancy
with the minimum/maximum values between the spinbox and the slider.
The test values come from a real case that was asserting in
ctkSliderWidget.
Fix ctkSliderWidget assert when changing decimals with Ctrl+'+'

For the test to work, ctkDoubleSpinBox::keyPressEvent had to be written.
The test values come from a real case where ctkSliderWidget asserted.
Other values were not triggering asserts.
Expose publicly ctkRangeWidget slider, min and max spinbox

It can be handy to tweak sliders and spinboxes.
Merge branch 'ctkdoublespinbox-decimalsbykey'

* ctkdoublespinbox-decimalsbykey:
  Expose publicly ctkRangeWidget slider, min and max spinbox
  Fix ctkSliderWidget assert when changing decimals with Ctrl+'+'
  Fix ctkSliderWidget assert when changing decimals with DecimalsByValue
  Expose ctkDoubleSpinBox::DecimalsOption to other widgets
  Add ctkDoubleSpinBox::DecimalsByKey, DecimalsByValue and ReplaceDecimals
Control the number of decimals in the ctkMatrixWidget display

Display the matrix values with the same number of decimals used to edit the
items.
Merge branch 'ctkdoublespinbox-decimalsbykey'

* ctkdoublespinbox-decimalsbykey:
  Control the number of decimals in the ctkMatrixWidget display
Expose publicly setDecimals and decimalsChanged
Merge branch 'ctkdoublespinbox-decimalsbykey'

* ctkdoublespinbox-decimalsbykey:
  Expose publicly setDecimals and decimalsChanged
Add ctkVTKAbstractView::useDepthPeeling
Merge branch 'ctkvtkabstractview-use-depth-peeling'

* ctkvtkabstractview-use-depth-peeling:
  Add ctkVTKAbstractView::useDepthPeeling
Fix unused variable warnings
Merge branch 'fix-unused-variable-warnings'

* fix-unused-variable-warnings:
  Fix unused variable warnings
Better support of decimals change in ctkCoordinatesWidget

The number of decimals can be changed from the ctkDoubleSpinBox
directly. Let's make sure the new number of decimals is not overwritten
by the coordinates widget.
Merge branch 'ctkcoordinateswidget-decimals'

* ctkcoordinateswidget-decimals:
  Better support of decimals change in ctkCoordinatesWidget
Cleanup ctkUtilsTests using QTestLib

Issue #348
Add support for min, max, inf and NaN in ctkUtils

Closes #348
Merge branch '348-order-of-magnitude-infinite-loop'

* 348-order-of-magnitude-infinite-loop:
  Add support for min, max, inf and NaN in ctkUtils
  Cleanup ctkUtilsTests using QTestLib
Add support for inf and nan in ctkRangeWidget

Issue #348