OpenSystemsDevelopment / qpdf

Remove needless calls to open, close, and fileno; call remove instead
of unlink.

Put a specific comment marker next to every piece of code that MSVC
gives warning 4996 for.  This warning is generated for calls to
functions that Microsoft considers insecure or deprecated.  This
change is in preparation for fixing all these cases even though none
of them are actually incorrect or insecure as used in qpdf.  The
comment marker makes them easier to find so they can be fixed in
subsequent commits.

Make them safer by avoiding any internal limits and replacing sprintf
with std::ostringstream.

Enable C4996, deprecation/security warnings, which helps for Windows 8
certification.  Stop enabling C4267, which was warning about
conversions between size_t and other integer types.

Also separate C and C++ warning flags.

Make --enable-werror work properly on msvc, handle extra warnings
flags for msvc in configure.ac instead of hardcoding into
make/msvc.mk, separate warnings flags into WFLAGS in autoconf.mk to
avoid duplication and to make it easier to override.

Add QUtil::hex_encode to encode binary data has a hexadecimal string,
and use it in place of sprintf where possible.

Change iteration to use size_t instead of int.  The code should be
equivalent in all reasonable cases, but the original way this was
coded was causing a test failure with gcc 4.8.0 on ppc64.  See
https://bugzilla.redhat.com/show_bug.cgi?id=915321 for additional
information.

When caching objects in an object stream, only cache objects that
still resolve to that stream.  See Changelog mod from this commit for
details.

Some distributions (like debian) don't want .la files to be installed,
but the responsibility for doing this should like in the packaging,
not in qpdf itself.

Fix exit status for case of errors without warnings, continue after
errors when possible, add test case for parsing a file with content
stream errors on some but not all pages.

Also move writing to null and parsing of content streams out of the
wrong if block.

This target creates autofiles.zip from a source distribution or fresh
checkout after autogen.sh has been run.  The resulting zip can be
unzipped over a fresh checkout to support easier building on Windows
from a clean checkout.

Change object type Keyword to Operator, and place the order of the
object types in object_type_e in the same order as they are mentioned
in the PDF specification.

Note that this change only breaks backward compatibility with code
that has not yet been released.

Add virtual methods to QPDFObject, wrappers to QPDFObjectHandle, and
implementations to all the QPDF_Object types.

This method allows parsing of the PDF objects in a content stream or
array of content streams.

These object types are to facilitate content stream parsing.

Next released version will be 4.1.0 since new APIs are being added.

With newer encryption formats, it is no longer possible to recover the
user password using the owner password.

This fix eliminates a false test failure on some platforms and makes
the binary test work properly whether characters with the high bit
set, when treated as integers, are negative or not.

Fixed spelling errors in previously published commits and update
spelling dictionary

When preparing the trailer for writing to the new file, trim a copy of
the trailer instead of the original file's trailer.

The upcoming 3.1 release contains non-compatible API changes, though
they only affect parts of the interface that are extremely unlikely to
have been used outside of qpdf itself.  The methods and data types
affected were used for communication between QPDFWriter and QPDF and
would have had no real use in end user code.

Also add copyright notice to a few public headers that were missing
one.

When writing a new stream, always remove /Crypt even if we are not
otherwise able to filter the stream.

Original code was written before we could shallow copy objects, so all
the filtering was done by suppressing the output of certain keys and
replacing them with other keys.  Now we can simplify the code greatly
by modifying shallow copies of dictionaries in place.

Read and write support is implemented for /V=5 with /R=5 as well as
/R=6.  /R=5 is the deprecated encryption method used by Acrobat IX.
/R=6 is the encryption method used by PDF 2.0 from ISO 32000-2.