NPC Greetings and Coloured Text in Dialogs

This is a clean copy of #2146 due to the dirty commits that ended up in that pull request.

There are also several areas that got caught up in some indentation fixes which I apologize for in advance since it makes this pull request appear much larger than it actually is.

Focus on the dialog.lua file changes specifically. The rest is just string changes to NPCs and indentation changes.