Fix Memory Leaks

[sarahsnow1]

Overview

Fixes memory leaks!

Proposed Changes

• Upgrades to LOST 2.3.0-SNAPSHOT which always uses the application Context when creating new LostApiClients
• LocationFactory is simplified and improved. It does not keep a static reference to a Context and instead vends a new client only if one doesn't already exist
• Static inner class in OverlayManager now uses a weak reference of OverlayManager
• Migrates MapzenManager to use the application context
• Updates tests for new LOST version and for Context updates
• Small cleanup in basic SDK sample Activity

Closes #338