Merge pull request #1 from amplab/master

merge
Added concurrent tests to MasterInfo
update documents
create full path
Merge pull request #197 from chenghao-intel/create_full_path

Create local folders if parent path doesn't exist
A couple minor fixes and cleanups

There were more, but I was too slow, and other people already fixed them :)
Minor improvements to resilience of Heartbeat Thread

Improvements include:

- The HeartbeatThread is now always daemonic, so it will not prevent the
Master or Worker from exiting.
- Any exceptions that propagate from the HeartbeatExecutor will be printed.
- mIsShutdown was made volatile, and Thread.interrupt() used, to ensure
  timely shutdown of the thread. Note that either one is sufficient, but
  without either of them, the JVM does not guarantee this thread ever exits.
Merge pull request #199 from aarondav/heartbeat

Minor improvements to resilience of Heartbeat Thread
Fix indentation
Re-throw fatal exception
fix a broken link in documentation
Merge pull request #201 from uronce-cc/cc

fix a broken link in documentation
fix issue TACHYON-73 in JIRA: change toFullPermission in UnderFileSystem.java to handle all posix permissions
fix indentation, change changePermission to setPermission
remove toFullPermission
Semicolon!
Merge pull request #198 from aarondav/fixes-local

A couple minor fixes and cleanups
Merge pull request #202 from uronce-cc/cc

fix issue TACHYON-73 in JIRA: change toFullPermission in UnderFileSystem...
minor bug fix, tweaks.
Improve issue TACHYON-90 (JIRA): use FQDN as hostname