Added possibility to return tuple from filterfunc

If the returned type is a tuple, it will be interpreted as first the
title (i.e. hovertext), then the content of the infowindow. If the
returned type is a string, it will be used as both the title and
infowindow content (the old behaviour). This means that older configs
are still compatible and need no changes.
specifying a directory name for a dimension should work now
updated tileset.py and genPOI.py and a few other stragglers
Add less verbose config option
updaded doc download links
Merge in pull request #865
Merge Pull Request #859
Allow unicode to be returned from a genPOI filter function
Updated documentation

* Added paragraph and example about returning tuples from a filter
  (Issue #859)

* Added section about manualpois
  (Issue #858, Issue #869, Issue #598)

* Fixed a typo in the FAQ

* Added logging to file to the FAQ
  (Issue #871)
use git to find current hash, should work with overviewer-as-submodule
JSObserver will show ETA, and the 'renderComplete' message will persist

Closes #784
Closes #786
Merge in pull request #872
Merge pull request #862
Make sure that regionset.type always has a value
Validate texturepath exists
Fix spawn markers

(Fallout from the arbitrary dimension name change)
Fixed nether rendering crash

The nether rendering mode was not properly handling x and z values
outside of the range 0 to 15.  This was causing an out-of-bounds
segfault when accessing the remove_block array.

Fixes #881
Fixes #851
Fixes #852
travis ci button now uses master branch only

it used to show the status for all branches, which means (right now at least)
it's always failing.
Follow symbolic links while finding region sets.
Fix error in documentation

No parenthesis on the import statement.