Changelog:
=========
* Also catch RuntimeError when importing PyPDF so that PyPDF or,
crucially, its transitive dependencies do not cause diffoscope to traceback at
runtime and build time.
* Factor out a method for stripping ANSI escapes.
* Strip ANSI escapes from the output of Procyon.
Signed-off-by: Wang Mingyu <wangmy@fujitsu.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>