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