Shape path creation

[mgthomas99]

Currently, the library's render methods follow the following instructions:

1. Create a new path
2. Load vertices into path
3. Render path
4. Destroy path

This is great for quick rendering as it means the user does not need to deal with managing paths, but it causes serious decreases in performance once the number of objects exceeds a trivial number.

Instead, the library should offer two functions per shape: one function for creating the desired path, and another for creating and rendering the path automatically. For example, rather than having just a evgRect(...) function, we should have a evgMakeRect(...) and evgRect(...) function, where the latter function simply calls the former, renders the path, and destroys it.