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
Add support for inf and nan in ctkRangeWidget

Issue #348
Reject inf single step in ctkRangeWidget
Merge branch '348-order-of-magnitude-infinite-loop'

* 348-order-of-magnitude-infinite-loop:
  Reject inf single step in ctkRangeWidget
  Add support for inf and nan in ctkRangeWidget
  Add support for min, max, inf and NaN in ctkUtils
  Cleanup ctkUtilsTests using QTestLib
Fix warnings in ctkTest and ctkVTKRenderViewEventTranslator test

Marking the function inline removes the "function unused" warning
Merge branch 'fix-compilation-warnings'

* fix-compilation-warnings:
  Fix warnings in ctkTest and ctkVTKRenderViewEventTranslator test
Proxy value:

WIP