Remove the unused and undocumented printer.print_replace (#385)

This function's use-case appeared to be to force blades to print as bases.
However, this isn't at all obvious from the name, and the arguments which can be passed in look outright dangerous.

If users want to print the base representation, they can just print `some_mv.base_rep()` instead.
If users want to perform arbitrary and meaningless textual substitutions, we should let them do so explicitly themselves.

I suspect no one uses this function anyway.

Author: eric-wieser

galgebra/mv.py

@@ -659,8 +659,6 @@ def _sympystr(self, print_obj: printer.GaPrinter) -> str:
                     s += term
             if s[-1] == '\n':
                 s = s[:-1]
-            if printer.print_replace_old is not None:
-                s = s.replace(printer.print_replace_old, printer.print_replace_new)
             return s
         else:
             return print_obj.doprint(self.obj)

galgebra/printer.py

@@ -63,22 +63,12 @@
 \newcommand{\eval}[2]{\left . {#1} \right |_{#2}}$
 """
 
-print_replace_old = None
-print_replace_new = None
-
 SYS_CMD = {'linux2': {'rm': 'rm', 'evince': 'evince', 'null': ' > /dev/null', '&': '&'},
            'linux': {'rm': 'rm', 'evince': 'evince', 'null': ' > /dev/null', '&': '&'},
            'win32': {'rm': 'del', 'evince': 'start', 'null': ' > NUL', '&': ''},
            'darwin': {'rm': 'rm', 'evince': 'open', 'null': ' > /dev/null', '&': '&'}}
 
 
-def print_replace(old='^', new='*'):
-    global print_replace_old, print_replace_new
-    print_replace_old = old
-    print_replace_new = new
-    return
-
-
 def isinteractive():  #Is ipython running
     """
     We will assume that if ipython is running then jupyter notebook is