by default nuget pack does not include project dependencies. this is suboptimal since it would require managing at least 5 nuget packages. this uses a workaround detailed here https://github.com/nuget/home/issues/3891 to copy the dependent dlls to the generated nuget package. this doesn't resolve the issue of how we publish the documentlayoutanalysis project, since it is the top of the dependency tree and we publish its parent, rather than it.
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.
support both xobject and inline images. adds unsupported filters so that exceptions are only thrown when accessing lazily evaluated image.bytes property rather than when opening the page.
treat all warnings as errors.
package license url is deprecated in favour of package license expression but nuget doesn't seem to support expressions properly for published packages yet so we'll keep the deprecated url for the time being. having both url and expression causes the build to fail.
small obvious performance improvements for file header passing and getting the encoding information using the existing reverse name to code map.
temporary 'safe' untested implementation of seac for type 1 charstrings.
make structure public
bump version of package and project to 0.0.3 (it had accidentally increased to 0.0.5)
