- fix a bug, where if the user specifies packages to be downloaded, their dependencies were never downloaded.
- allow cloning a specific branch specified in `<export>` tag in `package.xml`. See Readme for more info.
Example of using `branch` in `package.xml`:
xml
<?xml version="1.0"?>
<package>
...
<export>
<git_url target="depth_clustering" url="gitgithub.com:niosus/catkin_tools_fetch.git" branch="master" />
</export>
</package>