Add Master class as the CodeMate entry

News:
- Master will call other operators to do the jobs.
- Remove unnecessary FreeMarker library.
Avoid too long line when rewriting

Add a 'appendCode' method in FortranRewriter class to set a line length
limit. When a line is too long (e.g., longer than 80), cut it off with
break line character '&'.

This function needs further improvement to make the output more readable.
Make Scan operate one single file

To make CodeMate can be tested by other users, make Scan can operate on
single Fortran file.