Add StorageTier into Tachyon
fix some typo and format
small fix for getting block size
Fixed the userId changing issue [TACHYON-171]

The problem is that if a user opens a client connection and starts
writing a file, but finishes writing after a certain
timeout (user.master.client.timeout.ms), then the MasterClient will
close its connection before the file is written, then reconnect and get
a new userId, which will screw up the write.

I'm not quite sure why we automatically close the connection if it
hasn't been used for a while, as we aren't really wasting any resources
by keeping it open. This change removes the original heartbeat
mechanism, which tracks how recently the client has been used and closes
the connection automatically, with a heartbeat that pings the master to
check the connection, and closes the client only if it can't connect to
the master. Now on a long write (or any operation with the client that
takes longer than user.master.client.timeout.ms), we won't reconnect and
change the userId.
simplify code path of converting String to enum in StorageLevelAlias
Documentation fixes
Undid the changes to MasterClient retry logic
relocate docker

Signed-off-by: rootfs <hchen@redhat.com>
add vagrant recipe to deploy tachyon cluster on virtualbox and aws

Signed-off-by: rootfs <hchen@redhat.com>
removed compareTo from UiBlockInfo since its bad practice to define it without equals and hash.  Inspecting the code, it wasnt needed so removed
fixed issues caught by findbugs on WebInterfaceBrowseServlet
fixed unneeded code that compiler checks already.  Fixed array so it cant go past array
doc and check that vagrant version 1.6.5 is required
review feedback:change image name from TachyonSlave to TachyonWorker
added exponential backoff for master client
docs
max retry is set back to 1 second
updated based off feedback from checkstyles
remove unused Exceptions in WorkerStorage
review feedback: not use aws subnet_id right now

Signed-off-by: rootfs <hchen@redhat.com>