Saved KB/MB/GB bytes as constants to save multiplication.

Each time the 'dataSize' filter was called, the function did lots of
multiplication to get bytes per KB, MB, and GB to determine how to
print the string.

Moving the constants outside the function returned by the filter means
the multiplication is done only one time on app start up instead of in
each call.

* Added 1 digit to the right of the decimal point for GB. 6.5 GB is
  very different from 7 GB.

Review: http://reviews.apache.org/r/15579
Removed unnecessary wrapping .row from frameworks.

Single-column layouts in Bootstrap do not need to use .row .span-12
since width: 100% already has the same effect.

frameworks.html now matches the other tabs, slaves.html and offers.html.

Review: http://reviews.apache.org/r/15580
Added 'completed_frameworks' sorter for /frameworks.

Completed frameworks were added to the /frameworks page in commit
77c72f3639024168996ad3257908b558beed3996, but a table sorter was not
added. This makes it possible to sort the table by any of its columns.

Review: http://reviews.apache.org/r/15581
Fixed a bug in Web UI.

There was no check on the bounds of an array before attempting to read
it.

Review: https://reviews.apache.org/r/15640
Simplified os::hostname() in libstout.

Review: https://reviews.apache.org/r/11108
Shuffle offers before sending to frameworks.

This helps ensure fair allocation of resources.

Review: https://reviews.apache.org/r/11121
Added --enable-debug configure flag.

Review: https://reviews.apache.org/r/11605
Slave ping timeout may be increased by flags.

Review: https://reviews.apache.org/r/12885
Turned down noise from ZooKeeper.

Review: https://reviews.apache.org/r/11127
Use hostname instead of IP for redirection.

In the Web UI, the redirection does not work for hosts where the local
interface address is not publicly accessible.  For example, with EC2 the
redirection will not work.

This change writes the Master's hostname into ZooKeeper, thereby
allowing the redirection to work with private IP addresses.

Review: https://reviews.apache.org/r/11975/
On recovery fail, do rm -rf /tmp/mesos/meta.
Use libstout cache for slave completedFrameworks.

The list of retired (completed) frameworks is now a stout cache rather
than a boost circular buffer.  There are now key iterator accessors for
the cache class, and a removal member.

Review: https://reviews.apache.org/r/13599
Added a slave load hint for scheduler sorting.

With this change, the offers will include a slave load hint based on the
5 minute load average for that slave (returned from getloadavg()).
Frameworks can use this hint to select among otherwise similar offers,
as an optimization.

Review: https://reviews.apache.org/r/13675
Increase web UI reload delay.