GROOVY-3457: Fixing bug where line number of template error was incorrectly reported

o Added more granular unit tests correct line numbers on
  exceptions thrown when parsing/executing a template
o Added context reporting so that three context lines of code is
  now added to the thrown template errors even if it is a template
  parse (vs execution) error.
o Added and fixed various javadocs for StreamingTemplateEngine
GROOVY-3457: Cleaning white space
GROOVY-3457: Fixing javadocs for StreamingTemplateEngine
GROOVY-7186: Close URLConnection getInputStream() after testing for availability
Patch for issue GROOVY-7043
GROOVY-7171: Add List.getIndices()
GROOVY-7171: DGM getIndices methods (changed List to Collection and also added object array for completeness)
GROOVY-6952: Add List.removeAt(int) and Collection.removeElement(Object), because for List<Integer>, List.remove(int) and Collection.remove(Object) are troublemakers.
GROOVY-6952: Add List.removeAt(int) and Collection.removeElement(Object)
GROOVY-7212: Upgrade JUnit to 4.12
GROOVY-7175: add DGM indexed methods (javadoc typo)
Fix possible test failure depending on the order of execution of test methods
Tuple.equals() and Tuple2.equals() fix
GROOVY-7213: Trait composer should not generate bridge methods for private trait methods
Merge pull request #560 from yukoba/TupleEquals

Tuple.equals() and Tuple2.equals() fix
GROOVY-7215: Fix stub generation with traits
GROOVY-7214: Allow private static methods in traits
GROOVY-7175: add DGM indexed methods (rework indexed(Iterator) variant)
GROOVY-7161: Include inherited properties with @ToString
GROOVY-7216: Add check to see if the key is in the original map