Significant Refactor

[zyzek]

A significant refactoring effort:

• Renamed a whole bunch of stuff for sense, sanity, and consistency, removed abbreviations where possible;
• Factored out market player functionality respecting token issuance/burning into a new Mint manager class;
• Added many more convenience functions to market players, both oblivious and aware of fees;
• Ad-hoc reserve_bank actor factored out into a much more robust CentralBank market player;
• Randomizer behaviour is now much more sane, finally being calculated correctly. The market looks smoother as a result;
• Folded the FeeConfig class into the FeeManager;
• Broke managers up into different files inside their module, which has been renamed to managers;
• Broke the mesa_visualization_addons module into individual files and renamed it to visualization;
• Made the buy/sell premium/discount functionality available to market players;
• Bid and ask prices are now recorded and visualized over time;
• Made chart colours configurable for bar charts without affecting other chartist objects;
• Various vital bugfixes of logic errors resulting in incorrect behaviour;
• Docstrings and formatting improvements.

Closes #19.