Guillotine export extension too low DPI

[Nebojsa Ristic]

Hi,
export extension Guillotine is by default using 90 DPI, but that provide pretty much unusable exported files. Can that be fixed, so that Guillotine extension dialog have field where we can put desired export DPI.

I already modifed localy guillotine file so I can change my DPI manulay from extension dialog. In attachments are modifed extension files, use it to shorten bugfix, if you want.