Update StepProcessor and tests, build.sbt

* Now 'sbt console' imports the objects of the util package too.
* StepProcessorSpec: fixed the error case test.
* StepProcessorSpec: fixed test-data.
* StepProcessor: Implemented function to get the name af the app for first test step.
Update FileHandler, StepProcessors, tests, utils

* ManagedResource: Renamed to Lend, Function lend rename to apply. Object can be imported and used like a native feature.
* Try: Renamed to Opt. Can be imported as {Opt => opt) and the use looks better in code. Importing {Try => try} does not work.
* TestStep: Adapted to changes of Try.
* FileHandler: Adapted to changes or Try and ManagedResource.
* Errors: Added new error e10 for new scenario.
* StepProcessor: An almost working implementation. Helper functions still public for easy REPL experimentation.
* StepProcessorSpec: Fixed errors int expected results and test-data.
Update FileHandler

* Changed if - else use. 2 times as many lines but looks more readable in the end.
* getSourceFiles: In pattern matching use a1/a2 instead of arg1/arg2. Helps differentiate it from params of the function.