Replace deprecated methods

[AntumDeluge]

• 'setting_get' with 'settings:get'
• 'setting_getbool' with 'settings:get_bool'

May not want to merge this until after 0.4.16 release, as the new 'settings' object calls are not available in 0.4.15.

[paly2]

Okay indeed, I'll merge this when 0.4.16 will be released, as you said