Added ASSERT() to detect wrongly packed fields


sql/field.h:
  Fixed comments to right format
sql/opt_range.cc:
  Merged code
sql/sql_base.cc:
  Fixed indentation
sql/sql_insert.cc:
  Fixed comments to right format
sql/sql_select.cc:
  Simplify code
sql/unireg.cc:
  Simply code for calculating key_buff_length
  Added ASSERT() to detect wrongly packed fields