Reenable ScalaStyle on build for Cypher

The list of enabled rules is at this point minimal compared to the old config
but every violation is treated as an error and fails the build.
The next steps for this will be to keep adding more rules one by one
and fixing the existing occurrences.
Adding explicit key at relative path for ssh

This helps us run in TeamCity as well as on Jenkins
Add a reference to USING PERIODIC COMMIT to :help LOAD CSV in the browser
Add a doc reference for USING PERIODIC COMMIT
Fix: Manually revert removal of PredicateRewriter

Cannot yet kill it since we don't have a place for predicates for MERGE in the new ast
Fix: CypherCompilerTest that didn't run in jenkins
detecting teamcity runs

detecting teamcity runs and picking keys accordingly
Merge pull request #2084 from jakub-/periodic-commit-docs

Periodic commit docs
Merge pull request #2087 from jakub-/scalastyle

Reenable ScalaStyle on build for Cypher
Speculative build fix for Windows 2.1
Restructuring of Cypher manual builds

* Move cypherdoc from manual to community/cypher/docs and renamed it to graphgist
* Move uniqueness graphgist from manual/src/cypher into community/cypher/docs/cypher-docs
Add a import tutorial as a graphgist

* Removed two other manual sections
* Add //file: to graphgists so local files can be used
* Moved existing graphgists to live under community/cypher/docs