Rust FFI bindings for OpenTok Linux SDK

OpenTok Linux SDK FFI bindings for Rust.

These bindings are providing unsafe FFI API that can be used to interface with OpenTok.

The bindings are autogenerated with bindgen with some minor manual changes.

The current generation is driven by the build script. The equivalent bindgen invocation is:

bindgen libopentok/include/opentok.h -o src/bindings.rs  --whitelist-function 'otc_.*' --whitelist-var 'OTC_.*'

The current SDK version is: 2.19.1