SERVER-6157 Remove FastArray

It has no remaining users since the old external sorter was removed. Since it
has no advantages over a std::vector, it should never be used again.
SERVER-15111 Treat corruption of final journal section as an expected event
SERVER-13951 Add a WUOW around logOp in applyOps
SERVER-15192 Temporarily disallow rollback of logOp

Since there are currently logOp listeners that are not rollback safe we are
temporarily disallowing rollback of all operations once they get to the
logOp. This will work since (today) we only call logOp once we know an
operation will succeed and commit.
SERVER-13635 Heap allocate the OperationContextImpl for each request

Allocating it on the stack resulted in each request on a connection having the
same OperationContext pointer. This can mask places where we stash the
pointer and use it after the original has be destroyed, because a new one has
been constructed in the same place. Switching to a heap allocation should
minimize this, especially when using the debug allocator.
SERVER-15111 use boost 1.49 compatible copy_file
SERVER-15229 include collection scan or index scan direction in new explain output
SERVER-15089 remove fatal state and refactor rollback to use replcoord
SERVER-15255 fix unit test
SERVER-15195 Implement getHostsWrittenTo in ReplicationCoordinatorImpl
SERVER-14567 Implement checkIfWriteConcernCanBeSatisfied in ReplicationCoordinatorImpl
SERVER-14445 Remove waitUpToOneSecondForOptimeChange from ReplicationCoordinator
SERVER-15248 Introduce ScatterGatherAlgorithm interface and ScatterGatherRunner.

The ScatterGatherAlgorithm interface describes operations that a scatter-gather
process must perform.  ScatterGatherRunner uses a ReplicationExecutor to
execute a ScatterGatherAlgorithm.
SERVER-13635: make generic SortedDataInterface unit test
SERVER-15247 GroupCommand::parseRequest() read CodeWScope correctly
SERVER-14444 Implement stepDown functionality in RelicationCoordinatorImpl
SERVER-14600 rename canServeReadsFor() to checkCanServeReadsFor() in the ReplicationCoordinator
SERVER-14508 Rewrite geo parsing using Status
SERVER-10448 change default explain mode from queryPlanner to executionStats
SERVER-14444 Don't call stepDown in ReplicationCoordinatorImpl (yet)