fpspreadsheet: Major reconstruction of numberformat parser to facilitate creation of xml formats for ods. Some minor regressions in unit tests and fpsgrid demo to be fixed. Removed elements "Decimals" and "CurrencySymbol" from TCell (this information is taken from the format string now). Removed the built-in format nfFmtDateTime (makes life easier, use nfCustom instead).

git-svn-id: http://svn.code.sf.net/p/lazarus-ccr/svn@3156 8e941d3f-bd1b-0410-a28a-d453659cc2b4
fpspreadsheet: Remove testing code from excel8write.lpr

git-svn-id: http://svn.code.sf.net/p/lazarus-ccr/svn@3157 8e941d3f-bd1b-0410-a28a-d453659cc2b4