OpenSystemsDevelopment / qpdf

For now, --allow-insecure allows creation of files with the owner
passwords empty or matching the user password.

When removing unreferenced resources, notice if a page (recursively)
contains a form XObject with unreferenced resources, and count any
such resources as referenced by the page.

Use the first of ASCII, PDFDocEncoding, or UTF-16 that is capable of
encoding the string.

Add constructors that take a QPDF object so we can issue warnings and
create new indirect objects.

Create a computationally and memory efficient implementation of name
and number trees that does binary searches as intended by the data
structure rather than loading into a map, which can use a great deal
of memory and can be very slow.

Avoid calling finish() multiple times on the pipeline passed to
pipeContentStreams. This commit also fixes a bug in which qpdf was not
exiting with the proper exit status if warnings found while splitting
pages; this was exposed by a test case that changed.

Make some more methods in QPDFPageObjectHelper work with form
XObjects, provide forEach methods to walk through nested form
XObjects, possibly recursively. This should make it easier to work
with form XObjects from user code.

Also removes preclusion of stream references in stream parameters of
filterable streams and reduces write times by about 8% by eliminating
an extra traversal of the objects.

This reverts an incorrect fix to #449 and codes it properly. The real
problem was that we were looking at the local dictionaries rather than
the foreign dictionaries when saving the foreign stream data. In the
case of direct objects, these happened to be the same, but in the case
of indirect objects, the object references could be pointing anywhere
since object numbers don't match up between the old and new files.

The test suite now contains test cases that fail with both 10.0.1 and
10.0.2 and reproduce the internal error from #449.

Warnings issued on the output QPDF object were not suppressing
warnings since that option was only set on the input QPDF object.

Specifically, if a stream had its stream data replaced and had
indirect /Filter or /DecodeParms, it would result in non-silent loss
of data and/or internal error.

Wildcard expansion is different in Windows from non-Windows and
sometimes requires special link options to work. Add tests that fail
if we link incorrectly.

Issue #399 mentioned a use case for which qpdf has support, but the
fact that it is supported was not documented or in the test suite,
making it vulerable to accidental breakage.

StreamDataProvider::provideStreamData now has a rich enough API for it
to effectively proxy to pipeStreamData.