fpspreadsheet: Row height and column width reading/writing code for ods files complete. Test cases ok, but extremely slow speed of test application for numbertest and datetimetests. Changed units of row heights in worksheet: used to be points, is "lines" now (more consistent user interface - column width is in "standard characters", I prefer these units over centimeters because row heights/column widths become independent of screen pixels per inch this way)

git-svn-id: http://svn.code.sf.net/p/lazarus-ccr/svn@3118 8e941d3f-bd1b-0410-a28a-d453659cc2b4