Add version to the Atom Helper plist

Closes #368

atom.gyp

@@ -1,5 +1,6 @@
 {
   'variables': {
+    'version': '2.0',
     'pkg-config': 'pkg-config',
     'chromium_code': 1,
     'use_aura%': 0,
@@ -42,6 +43,7 @@
       },
     },
     'xcode_settings': {
+      'VERSION': "<(version)",
       'CLANG_CXX_LANGUAGE_STANDARD' : 'c++0x',
       'GCC_VERSION': 'com.apple.compilers.llvm.clang.1_0',
       'COMBINE_HIDPI_IMAGES': 'YES', # Removes 'Validate Project Settings' warning

native/mac/Atom-Info.plist

@@ -31,11 +31,11 @@
 	<key>CFBundlePackageType</key>
 	<string>APPL</string>
 	<key>CFBundleShortVersionString</key>
-	<string>2.0</string>
+	<string>$VERSION</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
-	<string>2.0</string>
+	<string>$VERSION</string>
 	<key>LSApplicationCategoryType</key>
 	<string>public.app-category.developer-tools</string>
 	<key>NSMainNibFile</key>

native/mac/helper-info.plist

@@ -4,6 +4,10 @@
 <dict>
   <key>CFBundleDevelopmentRegion</key>
   <string>en</string>
+  <key>CFBundleShortVersionString</key>
+  <string>$VERSION</string>
+  <key>CFBundleVersion</key>
+  <string>$VERSION</string>
   <key>CFBundleDisplayName</key>
   <string>${EXECUTABLE_NAME}</string>
   <key>CFBundleExecutable</key>