Hybrid bindings

[maierfelix]

The hybrid-bindings branch contains ongoing efforts into moving Vulkan structures and handles from C++ over to JS. Vulkan function calls and enums remain in C++. Vulkan related C++ memory is filled within JavaScript using TypedArrays, ArrayBuffers and inlined memory offsets (done using pseudo bootstrapping in the code generation process).

Benchmarks with the new hybrid bindings already show some improvements in both memory usage and performance, because the JS->C++ overhead is reduced.

This also results in a reduced package size, less compile times, more flexibility for the interfaces (e.g. error handling) and greatly reduces code complexity in both the code generator and the generated binding code.

Some further notes:

• Add asm.js for faster memory operations? Further investigate into asm.js context switching performance
• Strings and Numbers live inside a Structure's memoryBuffer only
• Structures are now flushed within JavaScript
• C++ Vulkan Structure reflection gets possibly moved to JavaScript as well

State of 4/13/19:

• Hybrid bindings tend to be a lot faster than the native bindings
• Memory usage is now reduced
• Better error handling
• Shared memory for nested structures