Fix an issue where Version/Release are interpreted as non-string values

Signed-off-by: David Greaves <david.greaves@jollamobile.com>
Improve checks and messages

Signed-off-by: David Greaves <david.greaves@jollamobile.com>
Tag --ver if it doesn't exist

Signed-off-by: David Greaves <david.greaves@jollamobile.com>
Create $DISTRO-master if it doesn't exist