added default values for desired configurable variables to server.properties
update on multiple variables
updates on server.properties
updates
minor cleanup
merge SytzeH: added defaults to server.properties

Merge pull request #1561 from SytzeH/sql-layer/serverPr
https://github.com/FoundationDB/sql-layer/pull/1561
Extend tracking of isolation levels through to the transaction service, where something interesting might happen.
Centralize selection of transaction scan options for operator.
Hook those together so that SET TRANSACTION ISOLATION LEVEL selects appropriate scan options for operators.
Allow getting scan options without a transaction for tests that create cursors and only then begin before opening them.
Need a getSnapshotFuture.
Add new isolation levels for embedded JDBC using negative ints.
Make default schema in embedded JDBC more reliable.
That new overload was a bad idea.
Also check before starting iterator, for the case of multiple statements.
Add snapshot IT showing that whereas serializable conflicts, this skews.
Add read committed IT showing that "long" scans complete with expected isolation violations.