Add Moving Average Convergence Divergence (MACD) study to QuantFigure.studies

		Parameters:
			fast_period : int
				MACD Fast Period
			slow_period : int
				MACD Slow Period
			signal_period : int
				MACD Signal Period
			column :string
				Defines the data column name that contains the 
				data over which the study will be applied. 
				Default: 'close'
			name : string
				Name given to the study
			str : string
				Label factory for studies
				The following wildcards can be used:
					{name} : Name of the column
					{study} : Name of the study
					{period} : Period used
				Examples:
					'study: {study} - period: {period}'
		kwargs: 
			legendgroup : bool
				If true, all legend items are grouped into a 
				single one
			All formatting values available on iplot()

def add_macd(self,fast_period=12,slow_period=26,signal_period=9,column=None,
				 name='',str=None,**kwargs):
		"""
		Add Moving Average Convergence Divergence (MACD) study to QuantFigure.studies

		Parameters:
			fast_period : int
				MACD Fast Period
			slow_period : int
				MACD Slow Period
			signal_period : int
				MACD Signal Period
			column :string
				Defines the data column name that contains the 
				data over which the study will be applied. 
				Default: 'close'
			name : string
				Name given to the study
			str : string
				Label factory for studies
				The following wildcards can be used:
					{name} : Name of the column
					{study} : Name of the study
					{period} : Period used
				Examples:
					'study: {study} - period: {period}'
		kwargs: 
			legendgroup : bool
				If true, all legend items are grouped into a 
				single one
			All formatting values available on iplot()
		"""

		if not column:
			column=self._d['close']
		study={'kind':'macd',
			   'name':name,
			   'params':{'fast_period':fast_period,'slow_period':slow_period,
						 'signal_period':signal_period,'column':column,
						 'str':str},
			  'display':utils.merge_dict({'legendgroup':False,'colors':['blue','red']},kwargs)}
		study['params']['periods']='[{0},{1},{2}]'.format(fast_period,slow_period,signal_period)
		self._add_study(study)