Rules adjustment

After a few play tests, the game turn out to have some flaws and error which may cause frustration for the players; therefore, there are some adjustment to make:

- The amount of cash player recive at the start of the game $100 -> $300. 

- Plants die in 3 turns if not watering  -> Plants die in 2 round if not watering. 

- The players can only buy plant at the Plant Station -> The players can buy plan at the beginning of their turn.  

- Plant will die if over water -> Feature removed. 

- Toxic Gas feature added.