Simplify, clean up and tidy TargetDirectory.
Ensure that long test names do not hit Windows path length limit.

o The Windows path length limit is 260 characters.
o The names of parameterized tests include the values of the parameters which
   can make them very long.
o This fix uses digests of the names for test directories rather than the names
   themselves to avoid the limit. We record the mapping so that we can do a look-
   up in case of test failure.
Delete messages.log
Merge pull request #1387 from benbc/2.0-test-directory-paths-shorter

Avoid Windows path length limit for test directories
Start adding failing Cypher examples. Work on docs related to indexes.
Ignore a test that is failing on Windows. Fix in progress.
Changes behaviour of LAST/HEAD/TAIL
they now all throw exceptions for empty collections
Cleanup of Cypher code

Removes code that handled patterns with optional relationships,
the type used pre-OPTIONAL MATCH.
Merge pull request #1394 from systay/cleanup

Cleanup of Cypher code
Merge pull request #1379 from systay/last-head-last-empty-throws

Changes behaviour of LAST/HEAD/TAIL
Adds documentation for MATCH with properties in it
Fixes bug in predicate rewriter

When moving properties from MATCH to WHERE, the PredicateRewriter would
get into a never ending loops, adding predicates and never removing them from
MATCH.
cypher: Move all modules into community/cypher parent