dataframe_rotation

from this

	id			data
0	client_id	1007896
1	income		7896.3
2							#empty row
3	client_id	1007896
4	income		569.6
5	outcome		9863.5
6	client_id	1009635
7	income		986.5
8	outcome		0
9	client_id	1002587
10	income		0
11	outcome		6989

to this

client_id		income		outcome
1007896			7896.3		#empty or nan
1007896			569.6		569.6
1009635			986.5		0
1002587			0			6989