Unit selection

Show selection box around the unit you selected. Improved some code.
All barracks building added

- All of the barracks buildings are now usable. Using the 64px texture.
- Created the prefabs, JSON, factory.
- Fixed bug with unit production overlay, which caused a flicker because
it starts are 0,0,0 position.
- Added a notification when trying to buy a unit and you dont have
enough gold.
- Edited level one so it has all of the barracks for testing.
Add select from code

Selection is added from code.
Fix for running from game

Temporary fix for testing code without going through the menu. Improved
level 2.  LevelManager static because we use that class in menu and in
game, seems better.
Code formatting
Capturebuilding fixed, added globalprefab

- fixed bug with capturebuildings. The new building was not created.
Code for that was removed by accident.
- Removed the swipecontroller from the _scripts and added it to the
_GlobalScripts.
- Added the _GlobalScripts prefab to every scene. It will auto destroy
new instances, only one is allowed. Doesn't matter if game is started
from menu or level.
- Fixed bug in level 3 where a position x was 7.90001 instead of 8. The
tile calculation needs these numbers in increments of 2.
Updated levels

- Water sprites correct type
- Deleted unused class
- Added space key for faster ending turn for debugging
- End game working now (test with level default)
Damage fix
Edited JSONS, prefabs and LevelManager
Added loading screen for better levelmanaging

- Whenever a LevelManager.LoadLevel is called it will go to a
loadingscreen where it will load the level properties. When done it
loads the entire level.
- This also works when you are starting inside a level. E.g. Level1.
- Added a GameObjectReferences to easy access _Scripts and _Global
prefab gameobjects.
Made the LevelsEnum in LevelManager private set
Added a resourcecacher.
Refactor some code

Simplified some statements
Changed some variable names
Merge commit 'ba6137c'