Merge branch 'master' into v0.6.0

# Conflicts:
#	src/ifcconvert/IfcConvert.cpp
#	src/ifcgeom/IfcGeomRenderStyles.cpp
#	src/ifcgeom/IfcGeomWires.cpp
#	src/ifcparse/IfcLogger.cpp
#	src/ifcparse/IfcLogger.h
#	src/ifcparse/IfcParse.cpp
#	src/ifcparse/IfcUtil.cpp
#	src/serializers/ColladaSerializer.cpp
#	src/serializers/schema_dependent/XmlSerializer.cpp