Allow printing PDF from blob

[diastremskii]

This PR suggests adding an option to print PDF from blob downloaded elsewhere in the application. This is useful to have a better separation between downloading the document and printing the document. Example use case: disabling the print button when a document starts loading. While it is possible to do with callbacks from printJS, it's much more simple when download and print are separated.

[MattFanto]

This would be a very useful feature any chance that this will be merged at some point?