Added income frequency

- Added years and quarters to the interface
- Created timer that increments the number of quarters in a year until it reaches four. After four, the quarter resets and the year increments.
- Renamed TowerData to GameData

project/src/autoload/gamedata.gd

@@ -0,0 +1,8 @@
+extends Node
+
+var tower_name: String
+var budget: int = 2000000
+var year: int = 1
+var prev_quarter: int
+var quarter: int = 1
+enum GameSpeed { SLOW, MEDIUM, FAST }

project/src/autoload/twrdata.gd

@@ -1,16 +0,0 @@
-extends Node
-
-var tower_name: String
-
-var budget: int
-var prev_budget: int
-
-func starting_budget(lev: int):
-	
-	if lev == 3:
-		budget = 5000
-	elif lev == 2:
-		budget = 10000
-	# Default to easy mode
-	else:
-		budget = 20000