PDFHummus package 4.5

Oh bit of jump here from 1.0 to 4.5. Also i'll start using v prefix on release tags...cause that what grownups do (so i'm told).
I'm just matching the cmake version variable to the release tags for the sake of convenience. There's no API break at all.

This version completes a move started with the previous one (4.4) and makes PDFHummus an installable package either using a remote repo (e.g. this one) or having built it locally. Installing the package works both if the package was created using bundled dependencies or no (depending on the USE_BUNDLED flag usage (on by default). Also added an ability to fallback on bundled dependencies in case they are not otherwise located with USE_UNBUNDLED_FALLBACK_BUNDLED.

When instlling PDFHummus package you can use any library in the package as a target dependency in your cmake file. So normally you'd use PDFHummus::PDFWriter, but you can also utilize the bundled dependencies e.g. PDFHummus::Zlib. might come in handy. Note that those dependency targets are only available if USE_BUNDLED is true (which is the case by default). otherwise only PDFHummus::PDFWriter is available.

What's Changed

• feature: converting the public facing cmake variables into options by @galkahana in #191
• Use unbundled corrections by @galkahana in #192
• Find package targets by @galkahana in #193

Full Changelog: 4.4...v4.5