Please unify coding rule & style

[toliner]

• Do not mix tab-indent & 4space-indent. (e.g. com.sots.particle.ParticleRenderer)
• Optimize imports (e.g. redundant imports using wildcard on com.sots.util.registries.PipeRegistry)
• Weather insert empty line after class declaration, before "return", before end of method, between imports and others or not?

I'm sure that your coding styles & rules(Eclipse defaults?) are much different from mine(IntelliJ IDEA defaults). I want you to see code on this branch. They are formatted by IntelliJ IDEA. All files are changed because of indents. Therefore, I think that you should define coding rule & style and format all code. (If you add editorconfig, it's better.)

P.S. This is the result of code analysis of this project by IntelliJ IDEA. Java compiler warn 1 unchecked cast & 25 use of deprecated methods.