Displays a matrix with scatter plot for each pair of
	Series in the DataFrame.
	The diagonal shows a histogram for each of the Series

	Parameters:
	-----------
		df : DataFrame
			Pandas DataFrame
		theme : string
			Theme to be used (if not the default)
		bins : int
			Number of bins to use for histogram
		color : string
			Color to be used for each scatter plot
		size : int
			Size for each marker on the scatter plot

def scatter_matrix(df,theme=None,bins=10,color='grey',size=2):
	"""
	Displays a matrix with scatter plot for each pair of
	Series in the DataFrame.
	The diagonal shows a histogram for each of the Series

	Parameters:
	-----------
		df : DataFrame
			Pandas DataFrame
		theme : string
			Theme to be used (if not the default)
		bins : int
			Number of bins to use for histogram
		color : string
			Color to be used for each scatter plot
		size : int
			Size for each marker on the scatter plot
	"""
	if not theme:
		theme = auth.get_config_file()['theme']

	figs=[]
	for i in df.columns:
		for j in df.columns:
			if i==j:
				fig=df.iplot(kind='histogram',keys=[i],asFigure=True,bins=bins)
				figs.append(fig)
			else:
				figs.append(df.iplot(kind='scatter',mode='markers',x=j,y=i,asFigure=True,size=size,colors=[color]))
	layout=getLayout(theme)
	layout['xaxis'].update(showgrid=False)
	layout['yaxis'].update(showgrid=False)
	sm=subplots(figs,shape=(len(df.columns),len(df.columns)),shared_xaxes=False,shared_yaxes=False,
					  horizontal_spacing=.05,vertical_spacing=.07,base_layout=layout)
	sm['layout'].update(bargap=.02,showlegend=False)
	return sm