Implement new skin

Fixes #20
Create ToolbarPosition extension

Fixes #27
Use ToolbarPosition extension in toolbar-image

Fixes #27
Update font

Fixes #29
Update styles to new font

Fixes #29
Create placeholders for add buttons

Fixes #29
Change toolbar add behaviour

Fixes #28
Add support for skins

Fixes #26
Add dark skin

Fixes #24
Add ocean skin

Fixes #25
Change default cunfiguration of ToolbarAdd buttons

Fixes #29
Change the version of AlloyUI to 0.2.2