fairly complex bug


mysql-test/r/partition.result:
  Merge fix
sql/partition_info.cc:
  Moved method from sql_partition.cc to the partition_info class
sql/partition_info.h:
  Introduced a number of charset related arrays
  Removed some bools that could be checked by checking arrays instead
sql/sql_partition.cc:
  Introduced a number of charset related arrays
  Removed some bools that could be checked by checking arrays instead
  Made method of common complex if-statement
  Made that method and check of partition function fields public methods
  to enable use from partition_info class.
  Moved method to partition_info class
  Optimised copy_to_part_field_buffers method to avoid as much as possible
  calculations in those. Also avoided double calls when both subpartitioning
  and partitioning
  Handled review comments
sql/sql_partition.h:
  New methods public for use in partition_info class
sql/sql_yacc.yy:
  Missed this in previous merge and review fixes