This changeset adds support for autoincrements to archive. It allows it to have them with both unique and non-unique indexes. 
Test cases will come in the next push (just doing this one so I can get a couple of reviews in). This is not the final patch. 


sql/field.h:
  Added val_int() method similar to the one like val_str() that will allow you to pop in another pointer and do a test.
sql/ha_archive.cc:
  Adds auto_increment support to archive. Cleans up a number of other small items.
sql/ha_archive.h:
  More additions for support of autoincrements