* Enable nullable annotations
* Remove unused Jetbrain annotations
* Ensure system using statements are first
* Improve nullability annotations
* Annotate encryptionDictionary is non-null when IsEncrypted is true
* Disable nullable for PdfTokenScanner.Get
* Improve nullability annotations for ObjectLocationProvider.TryGetCached
* Revert changes to RGBWorkingSpace
* Update UglyToad.PdfPig.Package with new framework targets (fixes nightly builds)
to make the project more useful and expose more usable classes we're rearchitecting in the following way. code used to read fonts from external file formats like truetype, adobe font metrics (afm) and adobe type 1 fonts are moving to a new project which doesn't reference most of the pdf logic. the shared logic is moving to a new flat-structured project called core. this is a sort-of onion type architecture, with core being the... core, fonts being the next layer of the onion, pdfpig itself the next. this will then support additional libraries/projects as outer layers of the onion as well as releasing standalone version of the font library as pdfbox does with fontbox.
