#90 Added much Custom Stuff

Added enum SystemIcons to mainly manage SystemNamedIcons
Added enum ImagesStyle
Added enum IconSize
Added CustomIcon
Added CustomImage
Changed all appearances of Icons to CustomIcons
Changed all appearances of Images to CustomImages
Fixed Background System
Added Setting ImageStyle
Added Setting IconSize
Changed DefaulListEntryView to use new stuff
Commented EditIconButton of FeedProvider
Rearrange Settings