Include helper symbols in print/pdf export

[arenol]

There should be a check box in the printing and PDF export dialog (akin to the include background imaged) that allows you to include helper symbols (default off).

The rational for this is that you may want to include the helper symbols when you are printing out field work base maps. For example, your map may include a symbol for non-ISOM boulders (boulders that are too small to be on the map) that are not to be printed on competition maps, but may prove useful when revising the map.