add short option like discussed in #20
add short option like discussed in #20

a -short option, which only outputs the titles of the entries, not the entire entries. So jrnl @maebert will display the full entries, but jrnl -short @maebert will output all lines containing the tag. jrnl -short without a search tag will display all titles
rzyns/jrnl,nikvdp/jrnl,Shir0kamii/jrnl,maebert/jrnl,cloudrave/jrnl-todos,flight16/jrnl,MinchinWeb/jrnl,MSylvia/jrnl,notbalanced/jrnl,philipsd6/jrnl,dzeban/jrnl,zdravi/jrnl,beni55/jrnl