Option for Update checking

[Riajyuu]

Add ability to check for updates, preview changelog, download and install update.

[digimezzo]

These features already exist:

• Update check + automatic update download and install: see Settings > Startup > Updates
• Change log: C:\Program Files (x86)\Dopamine\Changelog.txt

[Riajyuu]

You may misunderstand me, I mean it for Knowte.
These features indeed exist in Dopamine.

[digimezzo]

Oops. Sorry :)