[WIP] add three 0.112.x

[mcharytoniuk]

• Links to documentation: https://threejs.org/docs/index.html
• Type of contribution: addition

Other notes:
Types list is not complete, but it's definitely more comprehensive than existing 0.98.x types. I preserved most types from 0.98 as is, but also added generics for types like Mesh (Mesh<T: BufferGeometry | Geometry, U: Material>).

I didn't write explicit tests for types because I just didn't know there were tools for testing flow types. It seems too much work for me at the moment to write all those tests at once, so I am submitting those types as [WIP]. I will be still actively working on those to complete definitions and add test coverage, but I'd happily welcome any kind of help.

[AndrewSouthpaw]

Great work!

You're going to need to correct the Travis errors. Mostly they appear to be around fixing the inexact object types:

   Please add `...` to the end of the list of properties to express an inexact object type. (`implicit-inexact-object`)
    
                                           v
       181|   declare type ShaderDefines = {
       182|     [string]: string,
       183|   };

and so on.