build: Publish nuget from ps1

appveyor.yml

@@ -4,6 +4,9 @@ before_build:
 - git submodule update --init
 - nuget restore Perspex.sln
 
+environment:
+  myget_key:
+    secure: XOgD5bJUKNOS2kDDgb+affS4pDcslxALh+xvvnr1Koy0PjXlhILsBdNhxRe0KcNm
 
 configuration:
   - Release
@@ -16,4 +19,4 @@ artifacts:
 
 build:
   project: Perspex.sln
-  verbosity: minimal
+  verbosity: minimal

nuget/build-appveyor.ps1

@@ -4,4 +4,11 @@ Push-Location $dir
 
 sv version $env:APPVEYOR_BUILD_NUMBER
 sv version 9999.0.$version-nightly
+sv key $env:myget_key
+
+sv file Perspex.$version.nupkg
+
 .\build-version.ps1 $version
+
+
+nuget.exe push $file $key -Source https://www.myget.org/F/perspex-nightly/api/v2/package