v2.7.0

Removed features:

• Removed .Connected property, improving speed.

Changes & fixes:

• Removed --!native because I found out it decreases speed in this case.
• Heavily simplified linked list logic, improving speed.
• Swapped number-keys out for string-keys, as to avoid mixed-tables, improving speed and readability.
• No longer stores the connection metatable, improving speed.
• Now unlinks metatable instead of overriding with a no-op function.
• Now passes already-cached thread to reusableThreadCall, avoiding coroutine.running().
• No longer uses thread immediately, because it's actually slightly faster to resume once.
• Fixed an error that would occur when a thread calling :Wait() is resumed before fire.
• Comment changes and additions.
• Changed class names to PascalCase.
• Minor variable renamings.