Bug 694567: prevent double-free in pdf_open_raw_filter

If opening a filter in pdf_open_crypt throws, the stream is closed in
the used fz_open_* method and thus mustn't be closed again.
support jpegtables for TIFF images

This is required e.g. for 2314 - jpeg tables in tiff.xps.

This folds fz_open_resized_dct back into fz_open_dct instead of adding
further variations for calls with and without the jpegtables argument.
support /Alternate colorspace for ICC based

This progresses among others Bug689803.pdf and
Alternate_colorspace_for_ICCBased_not_supported.pdf
correctly set indexed colors in pdf_set_color

Required for 1879_-_Indexed_colors_wrongly_converted.pdf

Also, removing broken code in the same place (where mat->v[] is
overwritten right after being set in the L*a*b* case).
tolerate xobjects with invalid colorspaces

This fixes 2258_-_invalid_transparency_group_colorspace.pdf
Attempt to fix reflow.
Fix various compile warnings spotted by the cluster.
prevent heap underflow in pdf_read_new_xref
Implement continuous scrolling with 'j' and 'k'
Implement "zoom to full extends" functionality

The function pdfapp_autozoom zooms to fit the page to the window by computing
the aspect ratios of the page and the window and with that information either
zooming horizontally or vertically.
Maximize and auto-zoom when entering presentation

When 'p' is pressed, the window is put into fullscreen-mode and the
pdfapp_autozoom is called.
Make automatic slide advancement configurable

Pressing 'x' switches automatic slide advancement on or off.
Default is now off!
Make transition time and -type configurable

Entering a number followed by 'x' sets the transition time in tenths of a
second.
Entering a number followed by 'X' sets the transition type.
Add mechanism for displaying flags and settings