Add a new kind of group cursor that might commit from time-to-time.
Use it it SYS.DUMP_GROUP, as requested by client.
merge MMcM: Add a new kind of group cursor that might commit from time-to-time.

Merge pull request #954 from MMcM/akiban-server/dump-commit
https://github.com/FoundationDB/sql-layer/pull/954
Fix the test cursors by stopping the random switch for this test.
Cursors created on one server are not available on another.
merge tjoneslo: Fix the test cursors by stopping the random switch for this test.

Merge pull request #955 from tjoneslo/akiban-server/test-cursors-for-random
https://github.com/FoundationDB/sql-layer/pull/955
Re-fix the test-cursors test for the random connection access test.
merge tjoneslo: Re-fix the test-cursors test for the random connection access test.

Merge pull request #956 from tjoneslo/akiban-server/test-cursors-again
https://github.com/FoundationDB/sql-layer/pull/956