Allow queries to be specified as a dict.

Adds the ability for the queries parameters to be defined as a mapping
of zoom level to the query.  Undefined zoom levels are assumed to be null.
Allow S3 policy to be specified in config

Adds an optional 'policy' field to the S3 configuration allowing specific
permissions to be specified. The default is 'public-read'.
Return a transparent tile if coord is out of bounds.
added -L to example curl command
Merge pull request #181 from meetar/master

added -L to example curl command
more informative KnownUnknown

when layer.GetSpatialRef() returns None
Merge pull request #183 from probabble/patch-1

Return more informative KnownUnknown message when SpatialRef is missing
Add 'scale factor' option to Mapnik image provider

Adds the optional 'scale factor' argument in the config for Mapnik's
image provider. Allows a TileStache layer to be configured for retina.
Properly document 'scale factor' option.

Remove improper underscore
Bumped to 1.49.11 with various contributions
Increase decimal precision in Vector provider and output of scripts

Increased the decimal precision since the bounding box of the vector
provider was using %3f. %7f would be a better value for latitude
and longitudes (3% was good when we only did Web Mercator coords).
Fix UtfGridComposite to work with latest TileStache
Explicitly remove ubuntugis-stable from Apt sources list.
Merge pull request #167 from danzel/fix-utfgridcomposite

Fix UtfGridComposite to work with latest TileStache
Merge pull request #190 from mattmakesmaps/master

Update .travis.yml To Fix Broken Test Build
correct documentation for layer_id_key, layer_index
Add responding to "/favicon.ico"
Remove unnecessary dict update.
Merge pull request #157 from jwass/scale_factor

Add 'scale factor' option to Mapnik image provider
fix Pillow dependency