First public release for developers - minimal support.

Version 0.0.4 is actually the first public release and it works for most PDF files.

This version should raise exceptions when it fails.

I tested this version on all the PDF files I could find. Merging of PDF files now works across the board for all supported PDF files (regular PDF files and PDF files with either very simple compression or very simple encryption).

Stamping (or watermarking) pages worked on all the files except PDF files that were scanned and then had text recognition applied to them (OCR) - so that if the text layers were hidden (the OCR text is a hidden layer overlaid on the image), I couldn't stump text on those pages (the stumped text was also hidden).