add namespace attributes to __thrift_meta__, then we could access namespace info.

[truebit]

add namespace attributes to __thrift_meta__, so we could access namespace info. support #294

thrift = load("some.thrift")
namespaces = thrift.__thrift_meta__['namespaces']
cpp_namespace = namespaces.get('cpp')  # get ns by cpp lang
java_namespace = namespaces.get('java')  # get ns by java lang

[cocolato]

Suggested change

	thrift = threadlocal.thrift_stack[-1]
	scope = p[2] # language identifier, e.g. 'py', 'java', 'cpp'
	namespace = p[3] # namespace value, e.g. 'tutorial', 'shared'
	# Initialize __thrift_meta__ if not exists
	if not hasattr(thrift, '__thrift_meta__'):
	meta = collections.defaultdict(list)
	setattr(thrift, '__thrift_meta__', meta)
	else:
	meta = getattr(thrift, '__thrift_meta__')
	# Initialize 'namespaces' as dict if not exists
	if 'namespaces' not in meta:
	meta['namespaces'] = {}
	# Store namespace information
	meta['namespaces'][scope] = namespace
	_add_thrift_meta("namespaces", (p[2], p[3]))

namespaces metainfo should not be a one - way map. Implementing it in this way would be more reasonable.