Merge pull request #560 from bvssvni/master

Implemented `Draw` for `EllipseBorderColorContext`
Merge pull request #561 from bvssvni/master

Implemented `Draw` for `RoundRectangleBorderColorContext`
Merge pull request #562 from bvssvni/master

Implemented `Draw` for `BevelRectangleBorderColorContext`
Merge pull request #563 from bvssvni/master

Implemented `Draw` for `RectangleBorderColorContext`
Removed outdated comment
Remove unused import of crates
Fixed use statements
Removed `Field`
Started reduction
Further reduction
Renamed constructors
Added typle struct for exclusive shape variants
AddImage
Added SourceRect to ImageVariant
AddTween
Removed ColorContext
Put all `Add` traits in same module
Continue reduction
Removed EllipseBorderContext
Added fake `Context` constructors