This commit fixes loadufs command line to take parameters: bin/tachyon loadufs <TachyonPath> <UnderfsPath> [<Optional Excluding Prefixes;>]

(1) It adds a new method UnderfsUtil.getInfo/5 for implementing the new loadufs command line while keeping the old getInfo/4 for compatibility.
(2) It adds toString methods in PrefixList and TachyonFS for printing meaningful debug messages.
(3) It fixes list() in UnderFileSystemSingleLocal to return absolute paths, to be consistent with UnderFileSystemHdfs.
(4) It smooths out the uses of list() in other modules.
(5) It fixes docs/Syncing-the-Underlying-Filesystem.md accordingly.
auto-reformatted for code style
polishing code style
reformat code using the eclipse template
This commit makes the following fixes:

(1) It unifies under FS list() methods to conform to java.io.File.list(),
    which returns file paths relative to the given directory.
(2) It smooths out all usages of under FS list() for the above fix.
(3) It fixes the loadufs code with regard to the new list().
(4) It fixes the loadufs documentation accordingly.
fixed a few code style issues
rename UnderfsUtil getInfo() to loadUnderFs()
change local FS underfsAddress to /; fix a bug in excluding prefix-matching paths
Merge remote-tracking branch 'btachyon/master' into loadufs
add multiple signatures for loadUnderFs; allow for any levels of  exclude prefixes; update loadufs docs
polish loadufs code to use CommonUtils.concat
unit tests for methods implemented in this pull request
combine UnderFileSystemTest.parseTest cases
combine PrefixListTest.toStringTest cases
combine UnderfsUtil.loadUnderFs methods
further combine UnderfsUtil.loadUnderFs methods to keep only two
Merge pull request #168 from Du-Li/master

This commit fixes loadufs command line to take parameters: bin/tachyon l...
tweak for PR 168
fix tests
fix concat