Import from other Snippet Tools

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We should come up with away to import snippets from other tools such as textmate. This was raised in #17 and would make a nice addition. We'll need some UI to select the program your importing from, an upload field for uploading the snippet archive (what ever that looks like and dependent on source) we'll then need a report of the result and any issues it encountered. We should also allow this import system to be extendable so that other modules/instances could provide additional importers and logic to do it. They should also be able to adjust the import form.