Basic v8 Integration

closes #53
- Configures Gunship to include and link against v8.
- Adds "hello world" example for v8.
Move v8 Initialization into Gunship

- Gunship now holds a pointer to the v8 Isolate and initializes v8 on
startup.
Merge v0.2.0 onto v8_integration
Dynamically Load Startup Script

- Gunship now loads a startup js script and runs it through v8.
- Replaced instances of NULL with nullptr since that seems to still work
with C.
Setup Persistent v8 Context

- Adds basic skeleton for having a persistent context (is setup and used
across multiple functions).
Cleanup Previous Work

- Old Components and Locators have been removed to make it easier to
experiment with v8.
Create GameObjectComponent's from JS

- GameObjectComponents can be created within the scene through script.
The script objects do not yet have the component's id or index;
Set GameObect id and index

- The JS GameObject's now have their id and index properly set on
construction;
Create Camera from Script

- A camera can now be added to a game object from script.
- Added *.old.* files to the .gitignore to avoid source pollution when I
grab old files from history for reference.
Store Gunship Pointer in JS Object

This is the first step towards removing the gunship singleton.
Remove Gunship Singleton

- Removes Gunship singleton and replaces it with the instance held by
v8.
Add V8Helpers

- Adds Gunshipv8Helpers.h
- Finishes cleanup of Gunship singleton.
Add Mesh from Script

- Adds function for adding a mesh to a game object.
- Adds almost working SetPosition from script.
- Adds more extensive v8 helper macros.
Pass In Game Object Name from Script

- The name given when creating a game object from script is now
correctly passed to the GameObjectComponent.
Add Correct Mesh

- The mesh name provided to AddMesh() in script is now used when adding
the mesh entity;
Pass GameObject Position Through Script

- SetPosition() now reads in the passed arguments.
Adds LoadScript() Helper Function

- Gunship::LoadScript() reads in a text file and returns it as a
std::string.
Progress to Script Behaviors

- GameObject behaviors can be added from script. They are not yet called
every frame.
Almost Working Behavior Functions

- Behavoirs can be added, but they are not correctly bound to their
gameObjects.
Separate Startup Script and Game Script

- startup.js is now included with Gunship and is run as part of
initialization.
- Adds print() method to global js context to print debug info.
- Performs some style cleanup in Gunship.cpp.