Quicklisp-free version

[gunterkoenigsmann]

As the text portion of the wxmx file contents isn't compressed by default since 2013 and as there won't be a way to change the default in the upcoming wxMaxima release most .wxmx files can be read without an unpacker, an utility that does understand the .zip format and even without in-depth knowledge of the .zip format => attempted to modify the code to no more requiring quicklisp.

The result can be found in: https://github.com/gunterkoenigsmann/maxima-read-wxmx

Unfortunately I don't know how to tell the lisp just to tread the input as a sequence of bytes and therefore not to check the encoding: The text portion of the .wxmx file will be UTF8. But the rest of the file is binary and therefore currently is likely to raise an encoding error.