Bugfix: Format-Text must return parsed value, else value in textbox will be overwritten with "LastEditingNumericValue" if "IsUpdateValueWhenLostFocus" is enabled on lost focus by jholzer · Pull Request #55

Bugfix: Format-Text must return parsed value, else value in textbox will be overwritten with "LastEditingNumericValue" if "IsUpdateValueWhenLostFocus" is enabled on lost focus by jholzer · Pull Request #55 · Dirkster99/NumericUpDownLib

…ill be overwritten with "LastEditingNumericValue" if "IsUpdateValueWhenLostFocus" is enabled on lost focus

- Consolidate "FormatText" in base class (it´s nearly the same code in all derived classes)
- introduce abstract "ParseText" and type specific implementations for usage in in "FormatText", which was the only difference in the several implementations#
- return parsed value in "FormatText" to be used in e.g. _PART_TextBox_LostFocus, where it is assgined to "Value" (here´s were "Value" got lost)
- activate "IsUpdateValueWhenLostFocus" in demo application