bugfix for PRD-4713, possible fix to PRD-4739 (to your notice).

bugfix for PRD-4713, possible fix to PRD-4739 (to your notice).

Added feature for variable number of input fields for formula editor.
Added ability to remove parameters inside text_area/parameters_fields to have same reflection on formula.
If user inserts values in parameters fields, skiping some inputs - for example:
- we have function with infinity parameters,
- we added values in fields editor - in 1st and 3d field
- as a result will be (1;;2) (1st text field with 1, second empty, third with 2 value). Previous implementation was not able to handle such cases

Refactoring for editor classes, many unused methods and boolean checks removed.

For FormulaXXXElement.class if it is open bracket or semicolon etc. - represented values moved to static public fields.

Hope - libformula-ui will achieve much more improvements soon.