Add lastModificationTimeMs to Inode

Add lastModificationTimeMs to Inode. Update the Inode, InodeFile and
InodeFolder. Also update tachyon.thrift.ClientFileInfo by edit the
tachyon.thrift and re-generate the java code.
Update the WebUI

Add the Modification_Time to the WebUI
Complete the Last-Modification-Time

Complete the code for lastModificationTime. Update the parent's
modification time when create, delete or rename a file or folder, also
when create a raw table. When write to a file, update the file's
modification time and the file's parent's modification time.
Remove modification time when write a file

When write to a file, it does not change the metadata of the Inode, so
the lastModificationTimeMs doesn't need update.
Fix the Last-Modification-Time

Update the EditLog to persist the modification time.
Fix the behavior, now the lastModificationTime will be set whenever the
Inode's metadata changes.
Also update the test code of MasterInfo.
Fix the Last-Modification-Time

Use opTimeMs in the EditLog.
Call System.currentTimeMillis() in MasterInfo instead of
MasterServiceHandler.
Fix the Last-Modification-Time

Use opTimeMs both in EditLog and MasterInfo.
Add Tests for the Last-Modification-Time

Add Tests for last modification time into InodeFileTest, InodeFolderTest
and MasterInfoTest.
Fix the Last-Modification-Time

Fix and format MasterInfo for the last modification time.
documenting code
documented cache block
Merge pull request #294 from dcapwell/doc-worker

Doc worker
Merge pull request #275 from PasaLab/last-modification-time

Add the lastModificationTimeMs into Inode
masterinfo import reorder
Merge pull request #1 from amplab/master

merge