Publish Vulpes Preview 15 sources for desktop, Android and Tundra

Share Gaia assets and adapters, keep private profiles and development documents local, and update both public READMEs.

gaia/build/config/tablet/apps-engineering.list

@@ -0,0 +1,24 @@
+apps/bluetooth
+apps/bookmark
+apps/calendar
+apps/camera
+apps/clock
+apps/communications
+apps/default_theme
+apps/email
+apps/fl
+apps/ftu
+apps/gallery
+apps/keyboard
+apps/marketplace.firefox.com
+apps/music
+apps/pdfjs
+apps/ringtones
+apps/search
+apps/setringtone
+apps/settings
+apps/system
+apps/verticalhome
+apps/video
+apps/wallpaper
+outoftree_apps/*