add AE for arkref coref resolver
move function gettokenOffsets to class DockedTokenFinder, and expand it by adding heuristics.
Add tests to DockedTokenFinder
Add tests to StringUtil
updating coref implementation
LAP_ImplBase: extract building the empty AE for types to a separate public method
ArkrefClient minors
minor in StringUtil, DockedTokenFinder
move DockedMention to representation
create ArkrefInputFileMnager
create the "no trees" version of coref resolver (and arkref specifically)
clean ArkrefClient
arkref coreference resolver must throw appropriate exceptions in c-tor
add tests for arkref coref resolvers
Merge branch 'corefAE'

Conflicts:
	common/src/main/java/eu/excitementproject/eop/common/utilities/StringUtil.java
add variation to AbstractNodeUtils.getIndentedString
TreeCoreferenceInformation: add toStringWriteSubtrees()
improve tests
write CoreferenceResolverAE + Arkref
ArkrefClient cleaning