allows to use an existing workbook and an existing sheet, not just new
ones
more gitignores for eclipse
sheet.currentRow() can be used without calling nextRow(), so you can
write to existing sheets this way and overwrite existing data there:

SheetContext sheetCtx =
WorkbookContextFactory.useWorkbook(workbook).useSheet(sheet.getSheetName());

// move the cursor where the original cell is
sheetCtx.skipRows(sourceCell.getRowIndex()).setDefaultRowIndent(sourceCell.getColumnIndex());
// this will overwrite the original cell:
sheetCtx.text("overwrite!");
Merge pull request #3 from zluspai/master

Few changes that allows the poi builder to write data into existing Workbooks or sheets starting at an arbitary position