Apply changes applied from clang-modernize

Needed 1-2 cleanups by hand. 99% was automatic.

* The version that ships with ubuntu 14.04 seems to not work.
  I had to build from scratch

* Use cmake to generate the build commands that clang-modernize wants

```sh
cmake -DCMAKE_EXPORT_COMPILE_COMMANDS:bool=true ../ChaiScript/
```

* Use the clang-modernize tool. Note that you have to be pretty explicit
  about the include paths if you want it to also update your include
  files

```sh
../llvm-build/bin/clang-modernize ../ChaiScript/src/*.cpp -for-compilers=gcc-4.8 -include /home/jason/ChaiScript/include,/hjason/ChaiScript/include/chaiscript,/home/jason/ChaiScript/include/chaiscript/dispatchkit,/home/jason/ChaiScript/include/chaiscript/language -p compile_commands.json
```

* In my case, it left some unused `typedef`s behind, which I cleaned up.
Merge branch 'develop' of https://github.com/ChaiScript/ChaiScript into develop
Make `override` a #define for gcc 4.6 support