Allow a check for updates functionality against master branches releases

[jparnell8839]

• [ ] * Add "Check for Updates" under "About" dialogue
• [ ] * Add "Check for Updates at Startup" under "Settings" dialogue
• [ ] * Add "Check for Updates every:" and frequency under "Settings"

[jparnell8839]

Proposed for 0.6

[jparnell8839]

Partial completion in version 0.6.1

• [x] * Add "Check for Updates" under "About" dialogue
• [x] * Add "Check for Updates at Startup" under "Settings" dialogue
• [ ] * Add "Check for Updates every:" and frequency under "Settings"