v0.6.0a - fighting not that alone edition

New things:

• Added another active slot item: an auto sentry! It's very similar in usage to flask, but it does a different thing.
• 14 turret related affixes.
• Flask refills changed to energy crystals. It's functionally the same. It would be weird to use flask refill vials to recharge your turret.

Fixes and balance changes (thanks to stainedofmind and Darkbeetlebot for their feedback):

• Monster HP scaling slow-down setting now allows even bigger values (up to 0.5, was up to 0.2). I'm not really sure which value I should put as default here, need more testing.
• Auto-shotgun is now considerably more probable to drop.
• Auto-shotgun base damage buffed (4-8 to 5-9).
• Tome of change is now ~3x more likely to appear, and you can carry two at once.
• Backpacks base capacity is increased: +50 bullets, +10 shells.
• Backpacks' rocket and cell capacities scale faster with their level.
• Backpack positive capacity affixes' upper limits are raised 2x.
• Grenade launcher base rate of fire is buffed (approx. +20%).
• Grenade launcher base spread is lowered.
• Buffed plasma rifle damage spread (minDmg 5 -> 10).
• Buffed the Railgun (dmg 75-125 -> 100-150).
• Pistol is buffed. Mindmg 5 -> 8, clip size 10 -> 12. It's flogging a dead horse, but it's something.
• Lower clip size affix cap is lowered (-50% max -> -40% max).
• Bigger clip size affix cap is raised (200% max -> 350% max).
• Blue armor base repair is buffed (2.5 -> 3.5), green is nerfed (5 -> 4).
• Added some missed language tags.

Internal changes:

• The whole flask code is reworked to allow multiple types of active items instead.

Known bugs:

• Turret item uses flask sounds for now.