Update version to 1.14 everywhere

Update version to 1.14 everywhere

Merge pull request #526 from zeux/newver

Prepare for 1.13 release

Fix PUGIXML_VERSION macro

Also make sure the line shows up in grep when using the current version
number.

Fixes #478.

docs: Regenerate HTML documentation

Merge pull request #394 from zeux/cmake-yay

Don't define pugixml import target if it already exists

Merge pull request #391 from zeux/cmake-omg

Fix compatibility issue with CMake 3.10

Merge pull request #389 from mathstuf/fix-alias-compat-target

cmake: avoid ALIAS target

docs: Rebuild HTML documentation

scripts: Convert archive.py to Python 3

The changes are mostly mechanically converting str to bytes.