Integrate JetBrains Annotations

 - Intergrate JetBrains code-annotations to help ReSharper users
   enjoy better development experience:
 - Add [StringFormatMethod()] attribute for all public facing
   (Log|Trace|Debug|Warn|Error|Fatal) methods that use a format string
Merge pull request #270 from damageboy/master

Integrate JetBrains Annotations