Add index() and extract() to tester module.
Add index() and extract() to tester module.

index(paths) recursively indexes the tests in paths.
extract(test,[fn]) extracts the test to filename fn.

eugeneia/snabb,Igalia/snabbswitch,eugeneia/snabb,snabbco/snabb,Igalia/snabbswitch,Igalia/snabbswitch,eugeneia/snabb,alexandergall/snabbswitch,Igalia/snabb,snabbco/snabb,Igalia/snabbswitch,eugeneia/snabb,eugeneia/snabb,Igalia/snabb,snabbco/snabb,Igalia/snabb,Igalia/snabbswitch,snabbco/snabb,snabbco/snabb,SnabbCo/snabbswitch,SnabbCo/snabbswitch,Igalia/snabb,Igalia/snabb,alexandergall/snabbswitch,alexandergall/snabbswitch,alexandergall/snabbswitch,snabbco/snabb,alexandergall/snabbswitch,snabbco/snabb,Igalia/snabb,alexandergall/snabbswitch,SnabbCo/snabbswitch,alexandergall/snabbswitch,eugeneia/snabb,Igalia/snabb,Igalia/snabb,alexandergall/snabbswitch,SnabbCo/snabbswitch,eugeneia/snabb,eugeneia/snabb,snabbco/snabb