Implement a generalized file reader

The goal is to implement a flexible generic interface for reading molecular file formats (for example .smi, .sdf, and the compressed versions thereof). This will simplify the end-users' code significantly since they won’t have to include code to detect the file types themselves every time they process a file.

The expected results are a C++ implementation of a naive and a multi-threaded implementation of the generalized file reader for the RDKit along with a robust set of test cases. We implement a multi-threaded version of the reader since it will read files faster on modern computer hardware. Finally, I will implement wrappers for the reader so that it is accessible from within the Python, Java, and C#