#145 Pushpins in tree and table view

[lifesaver2000]

Although the newly added tracking behavior between the
tree, table and edit views is very powerful and useful,
there are times when a user may wish to step through
the table without the tree view changing or vice versa.
Adding a stick pin, as found in the editor window,
would be very useful when browsing through the data.

One difference in behavior though. Currently, if "Open
edit view when selecting in other views" is enable, and
the stick pin is selected, then selecting an entity in
another view causes the creation of a new edit window.
This should not be the behavior for tree and table
view with a stick pin enabled.

[Nils Meier]

agreed