Recursive compilation

With this patch, the special case of the "utility" folder in compilation is removed.
In fact now the IDE will be compliant to standard, and will copy recursively all file to compiled keeping the folder structure.
Also changed all library #include to be compliant with the standard.

Now you can import and export complex library and give a logical organization of your code's file.

TODO: The source in the sketch sub-folder will remain inaccessible from the IDE, I'll fix that soon with another patch