Also documenting some missing feature (decimal places ignored with direct text input)
getValueFor allows to check the value a given text would have
getOldValue can be used to check the previous value in a EGET_SPINBOX_CHANGED event
git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@6429 dfc29bdd-3216-0410-991c-e03cc46cb475