Minor refactoring in download/extraction part
New cache dir for download and extraction
Put GeoBase name in SCRIPT_NAME variable, reference to file with argv
Minor graph UI adjustements
Allow paths argument on GeoBases __init__.

This will be used only if source is None. local argument still has
a default to True for paths read from the configuration file.
If paths is given as an argument, local is False.
Normalize path structure as dict everywhere
Fix bug of tuple assignement
Move subdelimiters handling at the end
Small refactoring in paths handling at init
Changed a bit directives for archives, in order to have the same code on common operations.

Now archive: is replaced by file: and file: is replaced by extract:.
We convert all paths to the dict format with file: for normal paths.
This way all standard operations on path['file'] have the same code
(downloading, ...)
Fix error display
Move checkDataUpdates down
Adding comments in sources.yaml to explain how to make join
Fix tests
Draft for join implementation
Update release notes