short notation in status plugin + no tags if specified

[baaroth]

"short notation" as per git own PS1 convention, except

• kept your "nothing" on neither ahead nor behind (instead of u=)
• kept your (green) "clean" when no change (instead of nothing)
• advertise "no upstream" (instead of nothing)

e.g. (you'll have to imagine the color ^^):

/s/pao/pao-admin develop * u+3-10 $ gr @model @was status -q
S:\pao\build                      develop                 clean            
S:\pao\pao-admin                  develop                 *     u+3-10     
S:\pao\pao-api                    develop                 *%    u-31       
S:\pao\pao-api-model              mt.0322                 clean no upstream
S:\pao\pao-business-commons       develop                 clean u+1