Removed data_file, thermochimica_path, etc arguments from most functions, to allow more succint function calls, and instead exported them to a dedicated Config class so that these are class variables configured with an instance of tta, but they can of course be updated on the fly if they need to be changed, this is in line with intended/anticipated use.

Now using pyprojroot to create environment variables that can be succintly referenced by each script in this directory rather than explicitly having relative paths in each script

Finished long run coolant optimization, and separated fuel and coolant optimization into separate files

Added automatic path resolution. This can be useful if using the code in a jupyter notebook where it can be hard to determine absolute paths

Added better error handling in melting and boiling point calculating function, and updated README accordingly