[poppler] pdftocairo

[Adrian Johnson]

I have revisited the pdftocairo patches that Stefan Thomas was working
on a year ago that were based on a patch I wrote back in 2009. The
original code had some limitations particularly when trying to support
all the printing options. I have rewritten pdftocairo (except for
Stefan's cmake patch which I reused). This version supports all
applicable options from both pdftoppm and pdftops. I have also added a
couple of extra options:

 -icc <file>    (PNG only) specify an ICC profile for the output
                format. The profile will be embedded in the PNG file.

 -transp        (PNG only) use transparent page instead of white.

The attached patches:

 1. Use stdint.h instead of assuming the type sizes for the uintN_t
    types used by CairoOutputDev

 2. Fix a problem with the resolution information that PNGWriter writes
    to PNG files

 3. Add support for extra pixel formats to PNGWriter. RGBA is required
    to support the -transp option. The GRAY, and MONOCHROME formats
    allow PNGWriter to store these formats more compactly than
    if RGB pixels were used.

 4. Add support for writing ICC profiles to PNGWriter

 5. Add pdftocairo

 6. Add pdftocairo manpage

 7. pdftocairo cmake patch

 8. use show_text_glyphs() in CairoOutputDev so that text can be
    extracted from the cairo output

 9. Add the poppler version to PSOutputDev output to help with
    debugging pdftops issues by identifying the poppler version that
    created the file.