objects_osm2pgsql: use function to get all objects in bbox (for osm2pgsql based DBs)
pgmapcss_compile: add comments
pgmapcss_compile(): create function {style_id}_match; use in test.mapnik
Parse/Build: handle zoom selectors different from conditions
Parse/Build: handle type selectors different from conditions
pgmapcss_parse_selector(): bugfix cutting content string
Parse Selectors: split into link_parent, link_condition, object
pgmapcss_compile_selector_part(): move from pgmapcss_build_statement()
pgmapcss_parse_selector(s|_part)(): move types to pgmapcss_types.sql
Conditions: parse into data struct, compile from data struct
pgmapcss_compile_condition(): accept variable prefix as 2nd param
Move data type pgmapcss_rule_properties to types.sql (and rename from pgmapcss_properties_return)
Type pgmapcss_rule_properties: rename prop_list to prop_types
'where' Selectors: all selectors that make an object show
pgmapcss_compile_conditions(): compile an array of conditions
pgmapcss_compile_where(): return where clauses necessary for showing objects
objects(): use where clauses for index usage
objects(): speed up db queries by using multicolumn indexes
split pgmapcss_parse_content() from pgmapcss_compile_content()

- save all selectors and resulting properties in pgmapcss_compile_stat
pgmapcss_compile_where(): include implicit objects from set-statements