Fix LinkManager link removal
Add support for option argument
Support --unittest::testname

Allows you to run a single unit test from the command line
Don't wait on dead thread
deleteLink signal changed to linkDeleted
Move LinkManager testing to new LinkManagerTest
New LinkManager unit test
Guard again deletes not from LinkManager
Constructor should not add itself to LinkManager
Fix LinkManager bugs found by unit test

Largest change is that once a link is added to LinkManager it maintains
ownership and is responsible for delete. If you need to delete a link
use LinkManager::delete. Also added guard code to assert if a Link is
deleted outside of LinkManager.
Use new LinkManager::deleteLink api
Unit test changes
Remove double friend class

Fix linux compiler warning
Merge pull request #1023 from DonLakeFlyer/LInkManager

Link manager unit test and fixes