Remove doc repitition of the defaults

There's no need for the default values of the attribute to be repeated in the doc string itself.
Merge pull request #36 from gravitystorm/patch-1

Remove doc repitition of the defaults
add a 2.0.0 reference - refs #35
add marker-multi-policy to latest reference (currently targeting 2.2.x)
Add reference for 2.1.1, with marker-multi-policy addition

See also #40
Add 2.1.1 to the list of tested refs
Merge pull request #40 from mapnik/marker-multi-policy

add marker-multi-policy to latest reference (currently targeting 2.2.x)
Merge pull request #41 from CartoDB/ref-2.1.1

Add reference for 2.1.1, with marker-multi-policy addition
touchup marker-spacing doc
bump to 5.0.1 with new reference for 2.1.1 and new marker-multi-policy
bump to 5.0.2 with addition of shield-unlock-image
Add filter literals and new top-level filter item
Merge pull request #43 from mapnik/filter-literals

Add filter literals and new top-level filter item - closes #42
finish updating all versions after #43/#43
bump to v5.0.3 with new filter keywords support
add prototype tool for building out a datasource specific reference, using gyp like variables syntax to handle shared fields
add more csv and postgis options to layers.json reference - refs #44 and mapbox/tilemill#994
improve layer types validation and finish building out csv properties - refs #44 and mapbox/tilemill#994
Add encoding for appropriate datasources
touchup layer buffer-size doc as per change made in mapnik 2.2 (https://github.com/mapnik/mapnik/pull/1566)