Add play-cache module to build.sbt
ModelSaver returns an error when an unimplemented WidgetType is used
New route to check model statuses, checks compile status of all models with caching
Adds BuiltInModelLister to get a list of all files in the modelruns directory
FileLoader loads files that exist
ModelCompiler actor tests whether a model can be compiled
CompilationReporter aggregates and reports status of built-in model compilation task to observer
CompilerService uses actors to do the work of actually compiling, presents results to the user
Bump timeout on Actor test so Travis build passes
Test cleanup with null-check to make Travis happy (hopefully)