Unloads all add-on libraries previously loaded by Softimage,
allowing add-on developers to compile an add-on library while in
use in Softimage. The following add-on library types can be
unloaded: compiled operators, compiled custom commands, run-time
shaders, events.
These add-on libraries can also be unloaded from the Libraries
dialog located in the main menu under File > Addon >
Libraries. Once you have unloaded an add-on library, the Softimage
object connected to the library (for example, operators, shaders,
etc.) is no longer affected by the add-on until the library is
loaded back. You don't need to reload the add-on explicitly since
Softimage automatically reloads it when required. For instance, a
compiled operator library is reloaded when an evaluation is
required.