fpspreadsheet: Fix cell range selection issue in TsWorksheetGrid if grid is in edit mode. Fix ods reporting an error due to a worksheet with empty name. Fix some bugs added when introducing text overflow cells (frozen cells incorrectly painted, failure to determine row heights correctly)

git-svn-id: http://svn.code.sf.net/p/lazarus-ccr/svn@3564 8e941d3f-bd1b-0410-a28a-d453659cc2b4