v0.0.9 - Lifesteal and shop changes

Toddler napping --> Dada patching

Changes

1. I have added the lifesteal mechanic and upgrades. One stack of lifesteal equates to a 1% chance a projectile you fire heals you for 1HP when it connects. If you successfully heal, you cannot proc this effect again for 0.1 seconds. (This means if you have 100 stacks of lifesteal, every shot you fire that hits something will heal you for 1HP -- but at a maximum of 10 per second.)
   1. Common upgrade: 30g, +2 lifesteal
   2. Rare upgrade: 50g, +4 lifesteal
   3. Epic upgrade: 75g, +6 lifesteal
   4. Legendary upgrade: 100g, +10 lifesteal
2. I have made the base reroll cost in the shop much lower in later rounds. The old formula was that cost equaled double the round_number. The new formula is round_number + 1. This means early rerolls are in the same general zip-code of cost, but later rounds are significantly cheaper to start. (The cost of a reroll still doubles for that shop after each use.)

Soon To Come

1. Health regen, like a flat value of health you get back per second regardless of your activity. I understand that adding a second healing mechanic will make the game easier, but (A) it's an upgrade so it'll come at the expense of another purchase; and (B) I'd like to get the systems in place before fully pivoting to tweaking values. I have only gotten to Round 20 once anyway.
2. Permanent progression of some sort. Right now this is going to just be ships, cosmetics, etc. I have some ideas for different ships that shoot differently (charge shot? overheat meter?) so I'd like to add those. I do not expect to add as many playable characters to this game as there are in, for example, Brotato -- but I'd like to have a couple.
3. Once you've unlocked the other ships, we'll need a character selection screen.

Thanks for playing I love you.