Add codecov.io coverage collection from AppVeyor

Also had to add new project to redirect CTest output, add
separate batch scripts for AppVeyor because it doesn't handle
multi-line batch scripts in yaml properly, and other helper
scripts.

misc/installOpenCppCoverage.ps1

@@ -0,0 +1,19 @@
+# Downloads are done from the oficial github release page links
+$downloadUrl = "https://github.com/OpenCppCoverage/OpenCppCoverage/releases/download/release-0.9.6.1/OpenCppCoverageSetup-x64-0.9.6.1.exe"
+$installerPath = [System.IO.Path]::Combine($Env:USERPROFILE, "Downloads", "OpenCppCoverageSetup.exe")
+
+if(-Not (Test-Path $installerPath)) {
+    Write-Host -ForegroundColor White ("Downloading OpenCppCoverage from: " + $downloadUrl)
+    Start-FileDownload $downloadUrl -FileName $installerPath
+}
+
+Write-Host -ForegroundColor White "About to install OpenCppCoverage..."
+
+$installProcess = (Start-Process $installerPath -ArgumentList '/VERYSILENT' -PassThru -Wait)
+if($installProcess.ExitCode -ne 0) {
+    throw [System.String]::Format("Failed to install OpenCppCoverage, ExitCode: {0}.", $installProcess.ExitCode)
+}
+
+# Assume standard, boring, installation path of ".../Program Files/OpenCppCoverage"
+$installPath = [System.IO.Path]::Combine(${Env:ProgramFiles}, "OpenCppCoverage")
+$env:Path="$env:Path;$installPath"