Code cleanup and reformat

[DeadSix27]

MERGE AFTER #168

• Added proper License header to each source file
• Updated copyright year and added the biggest contributors
• Unified the formatting across every source file
• Added Notes for future reference, look for "//FutureNote"

Please see if this format is fine @YukihoAA.

[YukihoAA]

i reverted f6dd0e6 because it cause conflict.