Feature/take upgrade cost into account

[Urky]

When merged this pull request will:

• Fixed the bug upgrading past the disciplinarian perk
• Fixed a bug where equipmentproperties were not taken into account
• Added Split upgradepaths functionality
• Added Playerdecision switch to disable all logic behind multipath upgrading

[MLNW]

Closes #5 & #10

[MLNW]

@tbeswick96 might be best if you get around to give a review