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
Fix Qt designer crash when dropping spinbox in ctkCollapsibleGroupBox

ctkCollapsibleGroupBox (and ctkCollapsibleButton) were setting the visibility
of the newly added child spinbox to ON (at backtrace line 5).
As a side effect, QAbstractSpinBox::setLineEdit() was calling updateEdit()
which was trying to access some RTTI information that is not yet available
(because it was still in the spinbox constructor).

See below the backtrace:
#0  0x00007ffff6d78d50 in typeinfo for QAbstractSpinBox () from /home/julien/work/qt/qt-4.8.5/lib/libQtGui.so.4
#1  0x00007ffff65bb3b8 in QDoubleSpinBoxPrivate::textFromValue (this=0x1768890, f=...) at widgets/qspinbox.cpp:1279
#2  0x00007ffff64f9449 in QAbstractSpinBoxPrivate::updateEdit (this=0x1768890) at widgets/qabstractspinbox.cpp:1736
#3  0x00007ffff64f4e83 in QAbstractSpinBox::setLineEdit (this=0x1768860, lineEdit=0x1741840) at widgets/qabstractspinbox.cpp:686
#4  0x00007ffff64f87b9 in QAbstractSpinBoxPrivate::init (this=0x1768890) at widgets/qabstractspinbox.cpp:1558
#5  0x00007ffff64f401a in QAbstractSpinBox::QAbstractSpinBox (this=0x1768860, dd=..., parent=0x16bb7d0) at widgets/qabstractspinbox.cpp:152
#6  0x00007ffff65b8fae in QDoubleSpinBox::QDoubleSpinBox (this=0x1768860, parent=0x16bb7d0) at widgets/qspinbox.cpp:603
#7  0x00007ffff7283ab2 in qdesigner_internal::WidgetFactory::createWidget (this=0x8df9f0, widgetName=..., parentWidget=0x16bb7d0) at uilib/widgets.table:75
[...]
#41 0x00007ffff569706e in QEventLoop::exec (this=0x1489ac0, flags=...) at kernel/qeventloop.cpp:204
#42 0x00007ffff60d7438 in QDragManager::drag (this=0x1731a20, o=0x12b1780) at kernel/qdnd_x11.cpp:2028
#43 0x00007ffff6035bc1 in QDrag::exec (this=0x12b1780, supportedActions=..., defaultDropAction=Qt::CopyAction) at kernel/qdrag.cpp:284
[...]
#56 0x00007ffff66b53cd in QAbstractItemView::pressed (this=0x12b5f00, _t1=...) at .moc/debug-shared/moc_qabstractitemview.cpp:340
#57 0x00007ffff66a8b79 in QAbstractItemView::mousePressEvent (this=0x12b5f00, event=0x7fffffffcf90) at itemviews/qabstractitemview.cpp:1693
[...]
#68 0x00007ffff6024b9d in QCoreApplication::sendSpontaneousEvent (receiver=0x12b5f40, event=0x7fffffffcf90) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:234
#69 0x00007ffff601eb61 in QApplicationPrivate::sendMouseEvent (receiver=0x12b5f40, event=0x7fffffffcf90, alienWidget=0x12b5f40, nativeWidget=0x95b2e0, buttonDown=0x7ffff6dbaa58,
    lastMouseReceiver=..., spontaneous=true) at kernel/qapplication.cpp:3171
[...]
#78 0x00007ffff5696ee4 in QEventLoop::processEvents (this=0x7fffffffddf0, flags=...) at kernel/qeventloop.cpp:149
#79 0x00007ffff569706e in QEventLoop::exec (this=0x7fffffffddf0, flags=...) at kernel/qeventloop.cpp:204
#80 0x00007ffff569a0b8 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1221
#81 0x00007ffff601f776 in QApplication::exec () at kernel/qapplication.cpp:3823
#82 0x0000000000432a07 in main (argc=1, argv=0x7fffffffdfa8) at main.cpp:57

Closes #349
Merge branch '349-spinbox-crash-in-collapsible-widget'

* 349-spinbox-crash-in-collapsible-widget:
  Fix Qt designer crash when dropping spinbox in ctkCollapsibleGroupBox