master: do not use -p $port if unset in ssh url

If the port part is not specified in the address url, we should not
substitute it to 22.

This enables the choice to be made in /etc/ssh/ssh_config
master: adding translucent AREA+STACK
Merge branch 'pr/118' into devel
Merge branch 'pr/111' into devel
rrdcopy: add simple "normal" to "huge" migration

These changes fix rrdcopy so that it can copy normal->huge and huge->huge
(normal->normal and custom haven't been tested).

I also added a bit to the documentation
Merge branch 'pr/123' into devel
Merge remote branch 'origin/devel' into devel