Snapshot only related SSTables when sequential repair

patch by yukim; reviewed by jmckenzie for CASSANDRA-7024
Merge branch 'cassandra-2.1' into trunk
Allow cassandra to compile under java 8

patch by dbrosius reviewed by jmckenzie for cassandra-7028
adding parallel streaming support for sstableloader
adding StreamCoordinator.java for streaming - forgot on last checkin
unit test revisions for parallel streaming support compatibility
removed redundant sessionIndex in StreamMessage -> only need on init
rebase to trunk
update test to match parallel sig
pre new rebase
Revising usage to have ProgressInfo nested and retrieved from SessionInfo
intellij - new version decided I needed to apply umask on file save.  Blah.