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>
