Merge pull request #1930 from cleishm/loadcsv

Add LOAD CSV to Cypher
Fixed a couple of issues in BatchTransaction (test util)

so that it can use a configurable intermediary commit size and a progress
listener.
Renaming of one parameter in DocumentingTestBase.
Adds debug logging around index updates during recovery
Folding and rewriting of ASTs
Replace fixed rewriteTopDown/BottomUp methods with Rewriter objects