Add the example 4.e for condition numbers

Some imrpvements in the report.
Add condition number analysis

Remove unused files.
Update the .gitignore file
Update the .gitignore file.
Remove auxiliary files.
Update example 4.a
Update the example 4.b
Update the example 4.c (text)
Update the example 4.c
Emergency Backup
Chapter 4 - Example 4.d
Update the example 4.e
Update the example 4.e

- Add the module geopt.extras with the tango color scheme.
- Fix the color and line style in the example 4.e
- Minor fixes in section 4.
Minor changes to the example 4.e
Improvements to section 4.
Minor changes to section 4.
Remove the new command.
Merge branch 'develop'