Fix and improve plugin thoroughly (to 3.8.2)

[Adrianilloo]

This PR is the result of a really caring, considerable, durable and revised work that started off with the idea of merging the Silenci0's fork I found out from someone's AM Discord message.

Since then, I also fixed, polished and enhanced the plugin according to several middle-to-high issues I found out after the addition of this plugin to my HL2: DM server, which you can carefully check with each commit message involved, with enough level of detail.

Important things to consider:

• Mostly due to the updated Silenci0's fork state, the scripting files might only compile with SM 1.7+ now
• ~SM 1.11 compiler currently has a bug regarding dynamic array generation syntax that affects the plugin if compiled under that version. This could be easily solved by briefly replacing a certain float array declaration, but I prefer to wait as the SM team should publish a new fixed release soon.~ -> Fixed recently under SP version 1.11.0.6863
• This PR already includes (formatted) changes from #58

[HotoCocoaco]

Is TF2 workshop map support in this fork? Refer to: https://github.com/Silenci0/UMC/wiki/FAQ#can-i-add-workshop-maps-to-the-umc-mapcycle-list

[Steell]

Apologies for the delay, for whatever reason I never received a GitHub notification. This is fantastic work, I'm happy to accept this PR!