Add a filename (string) value parameter to keyword.

A file name string is in general a relative path string, relative to the pfs file at hand. If an absolute file name is entered, the PFS system will try to make the path relative to the pfs file, when the pfs file is written to disc, hence the relative string value in the PFS file will depend on the location of the pfs file for absolute file names.

Restrictions: The function is only valid within the scope of a keyword.

void AddFileName(
	string value
)

Sub AddFileName ( 
	value As String
)

void AddFileName(
	String^ value
)

abstract AddFileName : 
        value : string -> unit