Drop whipper caching (#336)

Whipper's caching implementation causes a few issues (#196, #230, [#321 (comment)](https://github.com/whipper-team/whipper/pull/321#issuecomment-437588821)) and complicates the code: it's better to drop this feature.

The rip resume feature doesn't work anymore: if possible it will be restored in the future.

* Remove caching item from TODO
* Delete unneeded files related to caching
* Update 'common/directory.py' & 'test/test_common_directory.py' (caching removal)
* Update 'common/accurip.py' & 'test/test_common_accurip.py' (caching removal)
* Update 'common/program.py' (caching removal)
* Update 'command/cd.py' (caching removal)

This fixes #335, fixes #196 and fixes #230.

Signed-off-by: JoeLametta <JoeLametta@users.noreply.github.com>

whipper/command/cd.py

@@ -99,7 +99,6 @@ class _CD(BaseCommand):
         self.ittoc = self.program.getFastToc(self.runner, self.device)
 
         # already show us some info based on this
-        self.program.getRipResult(self.ittoc.getCDDBDiscId())
         print("CDDB disc id: %s" % self.ittoc.getCDDBDiscId())
         self.mbdiscid = self.ittoc.getMusicBrainzDiscId()
         print("MusicBrainz disc id %s" % self.mbdiscid)
@@ -499,8 +498,6 @@ Log files will log the path to tracks relative to this directory.
                 self.itable.setFile(number, 1, trackResult.filename,
                                     self.itable.getTrackLength(number), number)
 
-            self.program.saveRipResult()
-
         # check for hidden track one audio
         htoa = self.program.getHTOA()
         if htoa:
@@ -541,8 +538,6 @@ Log files will log the path to tracks relative to this directory.
 
         accurip.print_report(self.program.result)
 
-        self.program.saveRipResult()
-
         self.program.writeLog(discName, self.logger)