Finish concatenate_mindboggle_surface_tables().

Formerly 'concatenate_mindboggle_tables()', this function now concatenates
specified surface tables, with the first row written only once at top,
and 'Subject: <subject name>' preceding each subject's table.
Revise concatenate_mindboggle_tables(), formerly concatenate_mindboggle_surface_tables(), to accept surface or volume tables.
Update select_column_from_tables() and select_column_from_mindboggle_tables() to include proper column header.
Update select_column_from_tables() and select_column_from_mindboggle_tables() to output stats and stats table.