OBT v1.1 - Enemies, Shields and Dark Magic

What's more do we have

This update brings some small rebalancing and bug fixes:

Removed Fullscreen Setting for Android build

- Toggling the fullscreen on and off was making the game crash in some devices.

Fixed the charge indicator on the pause settings menu

- It was using the indicator of the main menu. Blue instead of green.

- I could have none of that.

- Green for the pause menu.

The Shotgun number of shots was upgraded from 40 to 50.

- This is a quite powerful weapon.

- I like it.

- People think it's trash though because of the number of bullets.

- I have agree with them. Even if manage to optimize the bullet usage, you'll never reach the pickup on upper waves with bullets remaining.

- Now you'll still not reach the pickup with bullets remaining, but it has some more bullets.

Changed the pickups system so that you'll always have two different weapons to chose from.

- People wanted to avoid the shotgun.

- It was impossible when the only option was the shotgun.

- I was asked to fix it. So I fixed it.

- I found a bug where the machinegun can be the only option available.

- So the problem persists.

- But it appears to be only with the machinegun that it happens.

- So problem solved since it's not the shotgun.

- PS: Problem not solved at all. It can happens with all the guns. That's what I get for not testing things once more after refactoring the code...

Created a "boss" system

- There are some waves when the enemies are shown for the first time.

- They will then be the last enemies to be instanced.

- The Triangle, for example, is the boss of the Third wave.

- And I found a bug where the Quads prevent the boss from appearing.

- So, well, it sure break the point, huh?