toString representation for Query and its implementations
MasterQuery now extends AbstractQuery instead of Query
Move toString functionality for queries into AbstractQuery
Reverting import sort
Merge branch 'develop' into query-toString

Conflicts:
	core/src/main/java/de/learnlib/mealy/SymbolOracleWrapper.java
Merge pull request #13 from LearnLib/query-toString

toString representation for Query and its implementations