Improved overriding and base property access for presenters
Mark ImageHelperOnImageChanged as virtual to make it override

I was waiting for you to change it, but I guess that you don't have the time to do it. So if you accept it I can work with the source again.

Thank you
removed a couple of duplicate usings
Missing Dispose hooks (won't have made any practical difference to current activities - but should be there regardless)
Merge branch 'v3' of https://github.com/slodge/MvvmCross into v3
Merge branch 'v3' of github.com:slodge/MvvmCross into TibetBinding
Merge pull request #420 from MihaMarkic/cleaning

removed a couple of duplicate usings
Merge pull request #419 from jmgomez/patch-2

Mark ImageHelperOnImageChanged as virtual to make it override
Merge branch 'v3' of github.com:slodge/MvvmCross into TibetBinding
Build changes for 3.0.11 - System.Windows on PC (Dialog)
Change to Android Location Manager - some devices reporting issues with 5000, 2 default - so using 0,0

Expect this code to be replaced by new interface soon - see #413 and #398
Remove Touch PCL Crutches on PC
nuget test packages update
3.0.12 nuspec changes