reduced left and right margin

it was kind of waste of space, especially on mobile devices
added request parameter tsfmt (timestamp format)

with tsfmt=sql you get SQL timestamps instead of unix epoch ms.
right now only for csv (probably does not make much sense with json).
fixed channel details dialog title

jquery-gui does not like html entities here
changes for tsfmt request parameter

also some code deduplication in Interpreters getMin/getMax
code cleanup

consistent use of getFrom/getTo
handle unset icon in frontend
don't use from-timestamp for to timestamp-parsing

it was useful for relative times like "1 day", but was broken
for statements like "today" or "now".

behaviour is now:
- parse to timestamp (if given)
- parse from timestamp.
  * if none is given, use "to" minus 24h, or "now" minus 24h if there's no "to" timestamp
Merge pull request #45 from jahir/master

various fixes