Replace os.popen() with subprocess.Popen.

If the "gcc", "cc" or "objdump" command is not available, the code was
supposed to raise an OSError exception. But there was a bug in the code. The
shell code returns the exit code 10 if the required command is missing, and the
code tries to check for the status 10. The problem is that os.popen() doesn't
return the exit code directly, but a status which should be processed by
os.WIFEXITED() and os.WEXITSTATUS(). In practice, the exception was never
raised. The OSError exception was not documented and ctypes.util.find_library()
is expected to return None if the library is not found.

Based on patch by Victor Stinner.

Also synchronize with Python 3 examples. Based on patches by Matthew Boehm
and Alexander Schrijver.

by Jelle Zijlstra.

containing spaces.

Previously, when IDLE was started from a console or by import, a cascade
of warnings was emitted.  Patch by Serhiy Storchaka.

functools.partial objects.

for consistency with Python 3.

Implementation by Sean Rodman; test by Kaushik Nadikuditi.

This is how paste work on Windows, Mac, modern Linux apps, and ttk widgets.
The exception was X11 tk widgets.  Original patch by Serhiy Storchake.

  unused and outdated icons.

This matches the usage by BufferedReader, BufferedWriter, etc. Also document
and test that the write() methods should only access their argument before
they return.

Previous fix was only made to dead and removed code.