Computation times

00:02.993 total execution time for 4 files from intro:

Example	Time	Mem (MB)
2. Create a contour map (02_contour_map.py)	00:01.207	0.0
1. Making your first figure (01_first_figure.py)	00:01.047	0.0
4. PyGMT I/O: Table inputs (04_table_inputs.py)	00:00.465	0.0
3. Figure elements (03_figure_element.py)	00:00.274	0.0