Upload more presentation slide file types with higher quality results

With this update, we've completely rebuilt our presentation slide processing system.

We expect higher quality results across the board, as well as more accurate colors on the final output.

In addition, we now support a wide variety of file types beyond just PDF: KEY, PPT, PPTX, DPS, ODP, POT, POTX, PPS, PPSX, PPTM, SDA, and still PDF.

Note: Your slides will still be converted into images, so keep in mind that you may lose any animations or transition effects from your presentation.