housekeeping: Make ReactiveUI compile on VisualStudio for Mac

[glennawatson]

• Modified the Events projects to handle compiling on mac
• Android events now look for desired version on both windows/mac
• Modified the azure to run tests/ci on both windows/mac
• If not compiling on windows exclude uwp/net461
• Fix the build.sh to use the same as what the cake build team uses, and uses a global tool
• Turn off sourcelink for mac building temporarily. We don't use it for generating the NuGet packages anyway
• Modified Fody to not rely on TargetFramework for where to copy files from.
• Also fixed Fody compilation when it copies from the helper project, to wait until the sub-projects have a chance to compile first.

[codecov]

Codecov Report

Merging #1932 into master will increase coverage by 2.9%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master    #1932     +/-   ##
=========================================
+ Coverage   64.49%   67.39%   +2.9%     
=========================================
  Files          99       99             
  Lines        3585     4815   +1230     
  Branches      903      465    -438     
=========================================
+ Hits         2312     3245    +933     
- Misses       1138     1443    +305     
+ Partials      135      127      -8

Impacted Files	Coverage Δ
...rc/ReactiveUI/Activation/CanActivateViewFetcher.cs	33.33% <0%> (-16.67%)	⬇️
src/ReactiveUI.Winforms/Registrations.cs	54.54% <0%> (-7.96%)	⬇️
...ctiveUI/Bindings/Property/PropertyBindingMixins.cs	80% <0%> (-7.5%)	⬇️
...ReactiveUI/Scheduler/WaitForDispatcherScheduler.cs	75.86% <0%> (-6.5%)	⬇️
...ctiveUI/ReactiveCommand/CombinedReactiveCommand.cs	70.14% <0%> (-6.22%)	⬇️
src/ReactiveUI/Mixins/AutoPersistHelper.cs	91.39% <0%> (-5.44%)	⬇️
...ommand/CreatesCommandBindingViaCommandParameter.cs	91.17% <0%> (-5.12%)	⬇️
...activeUI/Bindings/Command/CreatesCommandBinding.cs	77.35% <0%> (-4.46%)	⬇️
...orms/windows-common/AutoDataTemplateBindingHook.cs	79.54% <0%> (-3.79%)	⬇️
...veUI/Interactions/UnhandledInteractionException.cs	37.03% <0%> (-2.97%)	⬇️
... and 85 more

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