updating all repositories from podfile sources
Config - Helper to get a directory of a given repo source
sources_manager - support aggregate with podfile sources location
Resolver use new SourceManager podfile aggregate
FIX crash in case no podfile present
Update previous test on #update_repositories_if_needed

Use source_names now
Remove extra space
Analyzer update repos when Podfile sources is empty

Podfile does not have a default repo source
Update Gemfile to use Core patch for Travis CI tests
Move podfile sources methods from Config to SourcesManager