Update buck build in Visual Studio

Summary:
- Always launch buck build for Build, but copy native library when it was changed
- Rename Facebook.Yoga.Mac.Test to Facebook.Yoga.Mac.Sample
- Add Facebook.Yoga.Mac.Tests for NUnit test.
  - "Run Unit Tests" menu item was activated for the target, but Mono still can't find libyoga.dylib
Closes https://github.com/facebook/yoga/pull/332

Reviewed By: emilsjolander

Differential Revision: D4408799

Pulled By: splhack

fbshipit-source-id: b3f5f9ebd8265cc152ca859176afbf54efa8f170

csharp/Mac/Facebook.Yoga.Mac.Sample/Info.plist

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleName</key>
+	<string>Facebook.Yoga.Mac.Sample</string>
+	<key>CFBundleIdentifier</key>
+	<string>com.facebook.facebook-yoga-mac-sample</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.0</string>
+	<key>CFBundleVersion</key>
+	<string>1</string>
+	<key>LSMinimumSystemVersion</key>
+	<string>10.11</string>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>en</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundlePackageType</key>
+	<string>APPL</string>
+	<key>CFBundleSignature</key>
+	<string>????</string>
+	<key>NSHumanReadableCopyright</key>
+	<string>${AuthorCopyright}</string>
+	<key>NSPrincipalClass</key>
+	<string>NSApplication</string>
+	<key>NSMainStoryboardFile</key>
+	<string>Main</string>
+</dict>
+</plist>