Major changes:
- Fixed a problem with parsing coordinates written with lower case (https://github.com/handsontable/formula-parser/issues/17);
- Fixed an inconsistent behaviour while parsing errors (https://github.com/handsontable/formula-parser/issues/15);
- Fixed wrong evaluation of expressions placed between parenthesis (https://github.com/handsontable/formula-parser/issues/14);
- Fixed parsing a cell coordinates expressions containing multiple dollar signs (https://github.com/handsontable/formula-parser/issues/13);
- Fixed parsing an empty string expression (https://github.com/handsontable/formula-parser/issues/12).