GoogleDocs plugin enhanced

GoogleDocs plugin enhanced!
Since today, Google API officially provides document download. So I can improve the GoogleDocs plugin to have all your docs exported to your 'My Google Documents' folder and directly editable inside it with a desktop application (like Word).

I've checked that the document history is not destroyed, but the modification steps (when you modify your document from your desktop application) are very raw (for example, "slide removed" + "slide added").
And beware, your document history is cleared when you move a document from a folder to another one within your My Google Documents folder (usually on your USB drive). Eventually it's very difficult to detect a file move on a filesystem, so, in Olipo sync engine: a file move == a file copy + delete.