[desktop] support pasting of (most) numbers formatted with decimal commas to the spreadsheet + tidying #4726

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37510 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
removing unused files, preparing CSVParser for porting to common

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37511 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e