Clean-up in add_field.
Clean-up in add_field.

 * Rename $expected_fields to $input_field_count
 * Compile split() regexes once
 * Prepend new field in position 1 when -f value is negative and the abs.
   value is too great.


git-svn-id: 036a1c5f902f528d79fbac72fb947c91fe594755@405 9f305d85-0c50-0410-b3e0-65f4174694de

dbushong/crush-tools,dbushong/crush-tools,dbushong/crush-tools,dbushong/crush-tools