Add option to hide table pipes and dashes

[bird-get]

Tables are currently presented like so (using avinfo for example):

key            | value             
---------------|-------------------
display name   | John Doe
username       | john.doe
language       | en                
group tag      | none              
hover height   | 0.000000  

It would be nice if there was an option to hide the pipes, so the output would be more like:

key            value             
---------------------------------
display name   John Doe
username       john.doe
language       en                
group tag      none              
hover height   0.000000  

and/or:

key            value             

display name   John Doe
username       john.doe
language       en                
group tag      none              
hover height   0.000000