Move file specific variables from BUFRFile object to new section object

From [email protected] on February 17, 2012 16:15:58

The following variables shoulb be moved from the BUFRFile object to an independant object:

edition
centre
update_sequence
message_type
message_sub_type
local_table_version
year
month
day
hour
minute
master_table
master_table_version

Original issue: http://code.google.com/p/python-bufr/issues/detail?id=8