Start on cache
Add more caching
Add null check
Don't create new resolver each time
Serialize output changemanifest
Add test to read in serialized data and display unique list of packagechanges
Try and catch when resolving issues.
Parameterise html test
Remove my test line
Split tfs urls by semicolon (to allow multiple)
Extract interface in prep for testing
Get one Tfs issue resolver test working
Add multiple url test (failing)
Fix breaking tests