Add support for context providers and provide a default implementation
Add @OutputVariables and @RequiredVariables annotations
Store the required and output variables per possible step
Add support for reporting custom errors (using Strings instead of throwables)
Throw original exception to preserve stacktrace
Check if all required variables are present in the context before running a step
Add unit test to test the @RequiredVariables annotation, WIP
Unit test now fails when a wrong or no error is reported
Merge branch 'develop' of https://github.com/Eernie/JMoribus into feature/variableAnnotations
Check missing output variable
Add unit test to test missing output variable error
Use value() instead of outputVariables() and requiredVariables()
Split testcase in seperate testcases for outputVariables and requiredVariables
Add success unit testcases
Add requiredVariables and outputVariables to PossibeStepTO and converter
Remove Context class
Merge branch 'develop' into feature/variableAnnotations

Conflicts:
	src/test/java/nl/eernie/jmoribus/Steps.java
Merge pull request #27 from Eernie/feature/variableAnnotations

Feature/variable annotations