Introducing TxCountsTrackingTestSupport

o  Moving PeriodicCommitAcceptanceTest to use FunSuite
Fix LoadCsvPeriodicCommitObserver must commit if updates are greater or _equal_ the batch size
Report line number information when failing during import with USING PERIODIC COMMIT LOAD CSV ...

o Some cleanup in EPB and renamed NullDecorator to NullPipeDecorator
o Introduce LoadCsvStatusWrapException
o Made sure LoadCsvPipe uses the correct external resource for loading (the one provided by the observer)
Ensure that each PeriodicCommitLoadCsvAcceptance test only turns green by exactly one way to commit

o Previously some of these tests could get green either by onNext() or onNotify() code paths which caused confusion.
  This happened due to the number of updates and the periodic commit value used and due to onNotify() using
  a batchSize * 2 safety factor
o Add UpdateCounter
Ensure that errors from server are correct when LOAD CSV adds line number information when USING PERIODIC COMMIT
cypher: Make toInt() handle float strings
Make math functions return null if given a null argument

o Introduce NullSafeMathFunction to simplify things
Add support for unicode dashes in rel patterns
Add support for unicode arrow heads in rel patterns
Merge pull request #2058 from davidegrohmann/2.1-loadcsv-periodiccommit-reporting

Add line number information on failure when USING PERIODIC COMMIT LOAD CSV
Merge pull request #2064 from boggle/master

Fixes to cypher math functions
Merge pull request #2066 from cleishm/unicode-dashes

Add support for unicode dashes in rel patterns

Forgive me.
Merge remote-tracking branch 'upstream/2.0-maint'
Cherry picking of two commits that went to 2.1 by mistake

07149dc4d0ffa67a3dd24b470f33a238cb4114e6
cypher: Make toInt() handle float strings

88c1a9a55cee9d0b0a13f62b11a34cc46573a7dc
Make math functions return null if given a null argument

o Introduce NullSafeMathFunction to simplify things
Fix TransactionErrorIT on Windows

Make sure we Cypher-escape the file URL.
Add USING PERIODIC COMMIT to Prettifier

o Untangle Prettifier parser along the way
Add support for FIELDTERMINATOR in LOAD CSV and remove ROWTERMINATOR from the parser
Convert PrettifierTest to CypherFunSuite
Added test for LOAD CSV handling different types of line termination
Add better error message for some problems