fpspreadsheet: Convert some more biff methods such records are written in a single block (biff2: WriteLabel, WriteNumber, all: WriteFormat, WriteBlank, WriteColInfo).

git-svn-id: http://svn.code.sf.net/p/lazarus-ccr/svn@3325 8e941d3f-bd1b-0410-a28a-d453659cc2b4