fix: empty string split behaviour 

from doc: 
Note: When the string is empty, split returns an array containing one empty string, rather than an empty array.
Signed-off-by:Eric Villard <dev@eviweb.fr>
refactor findRepos following the pattern exposed by Tim

see comment : https://github.com/timboudreau/gittattle/pull/5#commitcomment-4524829
Signed-off-by:Eric Villard <dev@eviweb.fr>
set HEAD then master as fallback branches

Signed-off-by: Eric Villard <dev@eviweb.fr>
Merge pull request #7 from eviweb/fix-jssplit

[BUGFIX] fix empty string split behaviour
Merge pull request #8 from eviweb/refactoring/findRepos

refactor findRepos following the pattern exposed by Tim
Merge pull request #9 from eviweb/branch-fallbacks

set HEAD then master as fallback branches