fix compile with boost 1.56 - refs #2368
fix css_grammar compile error with boost 1.56 - close #2366

Conflicts:
	SConstruct
adapt to ptree change in boost 1.56 - closes #2365
boost 1.56 support
adapt to new rtree interface in boost geometry >= 1.56 - refs #2367

Conflicts:
	plugins/input/geojson/geojson_datasource.cpp
backport geojson plugin fixes from master - refs #2319 and 2367

Conflicts:
	plugins/input/geojson/geojson_datasource.cpp