OpenSystemsDevelopment / qpdf

This is in preparation for restoring a QPDFObject.hh to ease the
transition on qpdf_object_type_e.

This commit was created by
* Renaming QPDFObject.cc and QPDFObject.hh
* Replacing QPDFObject\b with QPDFValueProxy (where \b is word
  boundary)
* Running format-code
* Manually resorting files in libqpdf/CMakeLists.txt
* Manually refilling the comment in QPDF.hh near class Resolver

Move responsibility for creating shared pointers to objects and cloning from QPDFObjectHandle to QPDFObject.

There are no automated tests yet, but committing work so far in
preparation for some refactoring.

Update getJSON() methods and calls to them

Run this:

for i in  **/*.cc **/*.c **/*.h **/*.hh; do
  clang-format < $i >| $i.new && mv $i.new $i
done

This comment expands all tabs using an 8-character tab-width. You
should ignore this commit when using git blame or use git blame -w.

In the early days, I used to use tabs where possible for indentation,
since emacs did this automatically. In recent years, I have switched
to only using spaces, which means qpdf source code has been a mixture
of spaces and tabs. I have avoided cleaning this up because of not
wanting gratuitous whitespaces change to cloud the output of git
blame, but I changed my mind after discussing with users who view qpdf
source code in editors/IDEs that have other tab widths by default and
in light of the fact that I am planning to start applying automatic
code formatting soon.

For std::string and std::vector, replace operator[] with at.  This was
done using an automated process.  See README.hardening for details.

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

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

git-svn-id: svn+q:///qpdf/trunk@709 71b93d88-0707-0410-a8cf-f5a4172ac649

git-svn-id: svn+q:///qpdf/trunk@651 71b93d88-0707-0410-a8cf-f5a4172ac649

git-svn-id: svn+q:///qpdf/trunk@642 71b93d88-0707-0410-a8cf-f5a4172ac649

git-svn-id: svn+q:///qpdf/trunk@607 71b93d88-0707-0410-a8cf-f5a4172ac649

git-svn-id: svn+q:///qpdf/trunk@599 71b93d88-0707-0410-a8cf-f5a4172ac649