remove unused classes and methods
extract config loading and assume config.yml file if none is provided
remove unused attr refs
extract config loading and make it more re-usable
introduce generic file loading and resolution

The previous methods of resolving a file was error prone and broke in
many cases if the file we’re looking for is in a JAR.
This approach introduces the FileUtil and ResolvedFile classes which
facilitate a better mechanism for finding files.

This makes heavy use of the Files and Paths API and usage of the old
File class should eventually be migrated to use the new method.

File resolution works by checking if the file exists on disk. If it
doesn’t it checks if it is on the class path.
If a file is found, regardless of where, the new API provides an
InputStream to the file as the preferred method of reading. If the file
is a directory then it provides a directory stream.
replace betty's chunked file and use the new input stream based file resolution
make sortable objects' priority mutable
additional module configs
make config injectable and transformer priorities configurable
adds support for multiple implementations of an SPI
fix some file resolution and stream issues
extract common logic to determine if a transformer can handle an object into the base class