Add LIBMTP_Get_Children() to read the list of raw IDs of a folder.

BUG=385307
R=thestig@chromium.org

Review URL: https://codereview.chromium.org/365823004

git-svn-id: http://src.chromium.org/svn/trunk/deps/third_party/libmtp@284892 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
5 files changed