Add doc written by @prattpratt

Tweaked syntax. Added section on appium predicate helpers
uninstall before install remote apk
Merge pull request #2651 from bootstraponline/prattpratt_doc

Add doc written by @prattpratt
Merge pull request #2654 from bootstraponline/uninstall_fix

uninstall before install
Fix DumpWindowHierarchy NullPointerException
Merge pull request #2657 from bootstraponline/npe_fix

Fix DumpWindowHierarchy NullPointerException
changelog for 1.1.0