add get_available_packages_from_url(), and add unit test.
- also fix the parser bug of nexus-4 device. ex: m-c-nexus-4-eng.
Merge pull request #145 from askeing/v2.0

add get_available_packages_from_url(), and add unit test.
Updated the var name
Merge remote-tracking branch 'mozilla/v2.0' into v2.0
updated flash_info.data
Merge pull request #146 from zapion/v2.0

Add setDefault()