move command now ask for a global move and check if source repository are local

All command now use select_image in repoman to select which image should be
select for use

search is now added to repoman and not by command

best option was dropped for all command

changelog command take now more than one image
diff command is no more limited to 2 args. Can be one with globbing
list -a is dropped, use *:* instead (this can be used in all command)

is command allow smart image selection like this:

- ftp/* => list all image in repo ftp
- ftp/*:4 => list all image in version 4 in repo ftp
- *:4 => list all images at version 4 in search path
- */*:4 => list all images at version in all repo
- debian => list all images nammed debian in search path
- debian* => list all images starting by debian in search path

execute clean command without asking confirmation

we need python-progressbar >= 2.3 to work with is.
We previously ship inside it because debian doesn't have 2.3 package available.
now we have built a debian package, we can remove code and add a dependency

old command line option are still present but no more in config file
this allow to override easily on command line config parameters

--no-sync as the same beneficts

this commit also make cachify more exception safe

if no filter given, list in all online repository
Also remove list -S, can be done by is -s ''

also use Repository.is_repository_name to validatage repository name

This commmit make a big cleaning inside IS binary, moving all code insides functions
and removing unecessary use of variables

also optimize tarball.getnames

dangerous options are last one

prepare and uprepare chroot functions now track non existant files
preparing are now done more carrefully about tricks

repo command can now purge cache of database