Fix includes and std:: namespace for fixed width integers and size_t

[csparker247]

• Change all instances of size_t to std::size_t and #include <cstddef>
• Add std:: to all fixed width integer types and #include <cstdint>
• Update to smgl v0.10.1 which incorporates similar changes.

@oceanusxiv please give this a try and let me know if I missed any includes.

Fixes #73

[oceanusxiv]

Thanks for this ultra-quick response! looks good to me.