Minor stuff: (#58)

* Minor stuff:

* Making a file called DISABLE_SUBMODULE_AUTOUPDATE in BuildChecker/ makes it not always run git submodule update.
* Added .mypy_cache to .gitignore.
* Made default platforms x64 (from Any CPU).

* Make git hooks +x.

Content.Shared/Content.Shared.csproj

@@ -3,7 +3,7 @@
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
-    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <Platform Condition=" '$(Platform)' == '' ">x64</Platform>
     <ProjectGuid>{26AEEBB3-DDE7-443A-9F43-7BC7F4ACF6B5}</ProjectGuid>
     <OutputType>Library</OutputType>
     <AppDesignerFolder>Properties</AppDesignerFolder>
@@ -97,4 +97,4 @@
     <None Include="packages.config" />
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
-</Project>
+</Project>