Added beginnings of view-map

which for now is really just view-plot with equal distance mapping on
(x, y) - still need to add Mercator projection, server-mode map tile
loading, etc.
Numeric color scale now works in view-plot
Fixing graffiti file

to provide reasonable (latitude, longitude) data.
OpsString, OpsFilterString

or at least the beginnings thereof. These perform some basic operations
on strings.