1.18 PowBall Renaissance update

Even though this upload has jumped two minor versions, there's not much new to the game. Mostly internal changes including linking to Steam's achievement system which involved moving over to Visual C++ from Eclipse &  MinGW, and adding adverts to the free demo Android version - not easy tasks, but I'm glad I did them.

Here is a breakdown for all your hard-core followers:

• More discrete health bar line under status
• F1 now brings up help page in level editor
• Minor bug fixes
• Exit screen removed
• Now using Visual C++