Powershell script for windows build

src/scripts/mkwinrelease.ps1

@@ -0,0 +1,25 @@
+if (-not (Test-Path env:QT_LOCATION)) { echo "QT_LOCATION is not set"; exit; }
+if (-not (Test-Path env:APP_VERSION)) { echo "APP_VERSION is not set"; exit; }
+
+$target="zcash-qt-wallet-v$Env:APP_VERSION"
+
+echo "Cleaning"
+nmake clean *>$null
+Remove-Item -Path debug -Recurse | Out-Null
+Remove-Item -Path release -Recurse | Out-Null
+
+# Run qmake
+echo "Configuring"
+& "$Env:QT_LOCATION\bin\qmake.exe" zcash-qt-wallet.pro -spec win32-msvc "CONFIG+=release"
+
+echo "Building"
+nmake *>$null
+
+# Make a dist directory in release
+New-Item release/$target -itemtype directory | Out-Null
+Move-Item release/zcash-qt-wallet.exe release/$target | Out-Null
+
+& "$Env:QT_LOCATION\bin\windeployqt.exe" release/$target/zcash-qt-wallet.exe *>$null
+
+echo "Zipping"
+Compress-Archive -LiteralPath release/$target -DestinationPath "release/$target.zip"