[mobile] Printing documents

[twiss]

Similarly to #206.

Chrome android has an option Print which can print to a cloud connected printer or to Google Drive or to a pdf. However, it doesn't support window.print(). Maybe we should file an issue about that, or maybe we should try to support the native Print button.

[ferndot]

Hmm, this might be a useful feature for Firefox Mobile. I would say, file a bug with them.