Example 02_03 alternative output and some insignificant formatting in other files

Simple alternative text output for Example 02_03 implemented, not really a true rework. The code does not execute correctly if the current (not dedicated) interpreter in Spyder is used, this is also true of the original version. Please see forum for discussion.

Some other formatting and grammatical changes randomly applied as reading through the code (mostly line length reductions in order to comply with PEP8).