I was wondering if anyone could tell me how to make it so that sublime text 3 automatically updates the sidebar when i add a new folder/file to the current project in finder
A bit late to the conversation, but I resolved this by turning off DropBox's Finder integration. There is a known issue with Yosemite 10.10.x https://www.dropbox.com/help/7144
Click on the dropbox icon in your tool bar, click the gear and then open preferences. Un-check Enable Finder integration. Then restart your computer.
Hope that helps.