implement Directory Reference

Directories
directory	alma
directory	atmosphere
directory	calanalysis
directory	calibrater
directory	casa
directory	components
directory	flagging
directory	images
directory	measures
directory	ms
directory	plotms
directory	scimath
directory	singledish
directory	spectralline
directory	StdCasa
directory	synthesis
directory	tables
directory	utils
directory	xerces
Files
file	array.h [code]
file	conversions.h [code]
file	conversions_python.h [code]
file	interrupt.h [code]
file	record.h [code]
file	type_record.h [code]
file	type_variant.h [code]
file	value_record.h [code]
file	value_variant.h [code]
file	variant.h [code]
file	version.h [code]