Couple of fixes

[jaredpar]

Fixes:

• Debugging workflow fixed by having a single long lived worker proc
• Fixed some issues with blocking on the UI thread
• Allow opening multiple assemblies

[DustinCampbell]

:+1:

I was thinking of moving this to 4.6 and making the connection async before I saw your change.

[Pilchie]

I just rebased this against Dustin's run single fix.