Allow single elements per file; programmatically build .clash through a directory lookup

[mkosler]

Give the user the ability to separate their skin into separate files. Given that, if they follow a certain naming scheme and directory layout, ClashBuilder could programmatically build a new clash file, rather than rely on the user to provide the information

[mkosler]

For example:

skin_name/
    button/
        button_normal.png
        button_hover.png
        button_down.png
    checkbox/
        checkbox.png
        checkbox_checked.png
// etc...