Just in time site loading - config flag

[KevinSheedy]

On some low power devices, it is desirable to lazy-load the websites to reduce the cup/memory load on startup. However, some users prefer to have all sites loaded immediately. I propose adding a config flag to enable this lazy loading behaviour. I suggest it should be disabled by default:

"lazyLoadTabs": false

[KevinSheedy]

Fixed in 0.4.0