reorganize tests, with clean workspace and repeatability

using WorkspaceTest as base class for tests
restrict exported guava packages
small fix in ErlParser
pathVars: use project's resolver

this allows using predefined vars like PROJECT_LOC
cleanup OtpRpcFactory
removed unused OpenService.getExternalInclude
merge ModelSearcherService into ModelFindService
extract Util.asStringList
small fixes
code cleanup
fix dependency
move IParent to IErlElement
move IOpenable to IErlElement
cleanup refactorings
remove unused IErlLibrary
setup handly dependencies
add new model interfaces
add minimal model+project implementations
minimal model tests
make model manager listen to resource changes