new fields, multiple disks, memlock/priority support

- New email.hasheader
- New packets.(src|dst), bytes.(src|dst), databytes.(src|dst) (issue #206)
- New payload8.(src|dst), payload.(hex|utf8), payload.(src|dst).(hex|utf8) (issue #209)
- pcapDir can now be a semicolon seperated list of directories, currently just round robin is supported
- UI: Fix Search/Actions showing up on second line on page load
- capture now does memlock and max schedule priority on startup (issue #199)
- when yara is disabled dont retain extra data
- parse email user names