More informative error messages and input boxes

Certain error messages could do with either being more informative or suggesting solutions. For example an ssh error is often encountered due to not having ssh pass installed so 'have you installed sshpass' could be added to it to prompt checking. Some features work without ssh pass so it is easy to overlook.

Similarly some input boxes may have limits on possible characters e.g. new project names. These should either be listed somewhere near the box or invalid characters (ideally with a list either of acceptable characters or unacceptable characters whichever is shorter) should be returned as the cause of an error where appropriate.

As these are noticed over time add them as bugs for simplicity and fix them as an on-going but low priority task.