list.js bugfixes and tweaks/minification

When new users registered the account page would list Name, Location,
Bio as "null" when there were missing values.

Also Timezone were displayed as "UTC +null:00" and no default value when
editing (first in list -12:00 became selected).

This commit makes the GUI display "N/A" instead of null-values for text,
also makes it an empty string in edit-mode.
The timezone is now defaulted to UTC +0:00 in both draw and
edit mode if no value exists.

This commit also makes some other tweaks such as utilizing jQuery
methods instead of string concatenation on some places.

A minified version (list.min.js) is also committed, compressed with yuicompressor
2.4.7 to cut some extra bytes if replaced in the views.