This should fully implement #1891 by adding an extra field to the edit
monitor page and an extra column to the database. The user can now
set the size of the packet to send, it defaults to 56. A maximum limit
of 65500 was chosen to ensure that the total size of the packet does
not exceed the IPv4 maximum packet size and to comply with the limit
imposed by Windows.
Signed-off-by: Matthew Nickson <mnickson@sidingsmedia.com>
