new file types to add

Was hoping to add in a few more file types to this lib.

**pcap**
`hex: D4 C3 B2 A1` & `hex: A1 B2 C3 D4`
ext: pcap
mime: 'application/vnd.tcpdump.pcap'

**cfbf**
`hex: D0 CF 11 E0 A1 B1 1A E1`
multiple exts: doc, xls, ppt, msi, msg
multiple mime types

Thanks!
