Add project call to top-level CMakeLists.txt file (#61)

Summary:
Running cmake shows this warning:
```
CMake Warning (dev) in CMakeLists.txt:
  No project() command is present.  The top-level CMakeLists.txt file must
  contain a literal, direct call to the project() command.  Add a line of
  code such as

    project(ProjectName)

  near the top of the file, but after cmake_minimum_required().

  CMake is pretending there is a "project(Project)" command on the first
  line.
```

Add a `project(Hermes)` to silence the warning.
Pull Request resolved: facebook#61

Reviewed By: mhorowitz

Differential Revision: D16421392

Pulled By: dulinriley

fbshipit-source-id: c53a68792389ba0368ef5c19a96ba7eb32a26d86

CMakeLists.txt

@@ -12,6 +12,8 @@ else()
   cmake_minimum_required(VERSION 3.6.0)
 endif()
 
+project(Hermes)
+
 include(CheckCXXCompilerFlag)
 include(CheckCXXSourceCompiles)