OpenSystemsDevelopment / qpdf

* Merge overloaded functions by adding default values
* Remove non-const methods that are identical to const methods

(patrepl and cleanpatch are my own utilities)

patrepl s/PointerHolder/std::shared_ptr/g {include,libqpdf}/qpdf/*.hh
patrepl s/PointerHolder/std::shared_ptr/g libqpdf/*.cc
patrepl s/make_pointer_holder/std::make_shared/g libqpdf/*.cc
patrepl s/make_array_pointer_holder/QUtil::make_shared_array/g libqpdf/*.cc
patrepl s,qpdf/std::shared_ptr,qpdf/PointerHolder, **/*.cc **/*.hh
git restore include/qpdf/PointerHolder.hh
cleanpatch
./format-code

Run this:

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

The PDF spec only allows UTF-16BE, but most readers seem to accept
UTF-16LE as well, so now qpdf does too.

* Use unique_ptr in place of shared_ptr in some cases
* unique_ptr for arrays does not require a custom deleter
* use std::make_unique (c++14) where possible

This makes it much more convention to use the initializeFromArgv
functions since you can use string literals.

Replace most of the calls to QUtil::copy_string with this instead.