updates to quantity module

added total quantity estimator module

implemented OPERA melting point prediction

adding exposure3 module with QRF model

correctly adding exposure2_module, color2_module

added tables and other edits

Update functions.py

merge with master (color additives)

added MP lookup and various bug fixes

added error output if Mw < 100 g/mol

Merge branch 'development' into smiles

updated to address feedback from Miguel on MDDT / master version

broke out exposure calculation into different functions, added comments, and moved polymer input to a separate .py file

new branch with chem id functionality started

updated function names

tidying things up

blueprint for exposure module

got blueprints working for facilitating module structure