The following commands have been renamed to better describe their
function and avoid confusion.
:VimwikiDeleteLink → :VimwikiDeletePage
:VimwikiRenameLink → :VimwikiRenamePage
:VimwikiGenerateTags → :VimwikiGenerateTagLinks (was already renamed in 3b5537f)
Calling the old commands still works but displays a warning message.
Fixes#90
__Problem__: VimwikiRenameLink does not rename dir1/toto url in dir2/tata
because the dirs (dir2 and .) were well crossed but badly inspected.
__Solution__: `blob(.ext*)` -> `glob(**/*.ext)` + find the relative URL
* Fasten: VimwikiRenameLink goes faster with cache
More: To compute old_url regex, use a cache dict because it is the same
for files in the same directories
* Util DeleteHiddenBuffer -> do not delete Vader buffer
* Test: Prettify: Util: teardown delete defined function
* Remove unnecessary trailing spaces
Note: list_VimwikiReturn.vader has some necessary trailing spaces
