Add option for reduced visual effects

[Hyperseeker]

There have been reports of users on lower-end mobile devices experiencing lags with the current visuals. This is unacceptable. Reducing the visuals for everyone may be a solution if it proves beneficial to the gameplay and the style.

Right now, the best solution is to add an option to make visuals significantly easier on the embedded GPU by reducing their complexity. For example, flash a solid border on foul instead of animating a gradient in.

Requires #6.