Minecraft wiki entry for Friendly_Update, associated text: Alpha v0.15.1, Alpha v0.15.2, Alpha v0.15.3, and Alpha v0.15.4 fixed numerous bugs and crashes.
Alpha v0.15.6 added some features specific for virtual reality, and also fixed some bugs and crashes from Alpha v0.15.4.
Alpha v0.15.7, Alpha v0.15.8, Alpha v0.15.9, and Alpha v0.15.10 added various texture packs and skin packs.