Use love.graphics.reset() to initialize graphics settings.

[ENH] Now nexus.graphics.initialize() will use love.graphics.reset() to
initialize graphics settings.
Remove nexus.database.update() and nexus.resource.update() functions.

[DEL] Remove nexus.database.update() and nexus.resource.update()
functions. The two are useless.
Move nexus.console to nexus.scene.console.

[MOD] Move nexus.console to nexus.scene.console.
Add message manager.

[NEW] Add message manager.
[NEW] Add nexus.input.reload() to reload current input devices.
[NEW] Add nexus.graphics.clear() to clear all the image data.
[ENH] Support skip splash for reloading game or return to title screen.