Add a changelog file inside isimage with a custom format which allow
image creator to quickly show update between images

Add a isversion field inside isimage which tell which version of installsystems was used to build image

Also fix some bug in PipeFile

This commit introduce remote repository and file accross ssh

currently db badly create if directory already exists before creation

We now use PipeFile to handle complex file type and compute md5 and filesize.

This commit add the following features in installsystems:
- A download progress bad
- check size before download
- check size after download
- check md5 after download

Signed-off-by: Seblu <sebastien.luttringer@smartjog.com>

Seblu: Fix too many things...

Signed-off-by: Seblu <sebastien.luttringer@smartjog.com>

$ is del description
Error: not a gzip file

$ is del description
Error: Unable to open image description: not a gzip file

best mode search best version across all repo and not the first

This is a better way of doing things. This help to have a better display of
where is causing latency

this allow to register breaked or offline repository wihtou breaking all is