Sets footer text and header margin for the worksheet.
 SetFooter(
 SetFooter(Excel headers and footers are generated from string with special formatting in them.
Formatting tags:
&L - Left Justification
&C - Center justification
&R - Right Justification
&P - Page number
&N - Total number of pages
&D - Date
&T - Time
&F - File name
&A - Worksheet name
&Z - Workbook path
&fontsize - Font size - where fontsize should be replaced by 2 digit font size
&"font,style" - Font name and style
&U - Single underline
&E - Double underline
&S - Strikethrough
&X - Superscript
&Y - Subscript
If no justification is specified in the formatting tags then text is by default centered.
Example text with flags
"&LSome test"    - Will left align the text "Some test"
"&LSome&Cfooter&Rtest" - This will put "Some" to left, "footer" centered and "test" to right. 
"&CPage &P of &N" -- this will center "Page 1 of 3"
"&C&\"Times New Roman,Regular\"Test"  -- This will center "Test" using Times New Roman Regular