Updating submodules
What's new updates to README.md
Merge pull request #230 from khawkins/unstable_master_merge

Mobile SDK 1.5 release (unstable -> master)
Adding upgrade notes from 1.4 to 1.5
Merge pull request #232 from khawkins/upgrade_notes

Adding upgrade notes from 1.4 to 1.5
Updating versions, binaries
Merge pull request #233 from khawkins/unstable

Merging master into unstable