[Maxima] documenting share/contrib & a few test failures

[Dieter Kaiser]

Hello Bartan,

Thank you for the report. I will adjust the accuracy of the tests.

The last days I have not worked on Maxima. I have tried to install a Linux
(Ubuntu) on a Notebook, because I am interested to have a second platform for
programming and testing Maxima. 

Because I have no experience with a Linux, it take some time to get all to work.
I have not finished the installation.

One point I have observed is, that it is possible to install a Maxima 5.13
package. But the testsuite does not finish. Perhaps I have not enough memory on
the Notebook.

Dieter Kaiser