Change all of the component tree helper objects to use LIB_IDs instead of
LIB_ALIAS pointers. LIB_ALIAS pointers are dangerous to use because they
can be deleted in the symbol library editor while the component chooser
dialog has copies of them. With LIB_IDs, the LIB_ALIAS pointer is found
on demand and can be guaranteed to be valid.
Update the chooser dialog to load the symbol library table instead of the
libraries defined in the project file and return a LIB_ID instead of a
LIB_ALIAS pointer.
Modify SCH_BASE_FRAME::SelectComponentFromLibrary() to handle the LIB_IDs
returned from the component chooser dialog.
Mikolaj Wielgus
Wayne Stambaugh
Chris Pavlina