Target Locking Persp and Ortho Views

This library was a response initially from Steven's question here: http://www.flexsim.com/community/for...ead.php?t=1170
I've created this thread so it's easy to find in the future.

This library allows you to open new persp and ortho view that will lock onto an object using the 'T'- left-mouse-click combination ('T' for 'target'). You can then easily rotate around the object using the normal right mouse button drag. You can clear the target lock just by pressing the left mouse button in the ortho/persp view.

The target object can be in a hierarchy of visual tools or other objects and can even be elevated in the z direction (as per the original request). It can also be a flowitem. The viewfocus can also be a container - it doesn't have to be the model.

I've tried to limit or account for angles which caused div/0 values and might cause the logic to lock - but without full testing please be careful and save your work first and regularly. If you experience problems please post them here and I'll try and cater for or correct them.

Jason