Small typo fixes in docs and expanded on android setup for mac osx
Merge pull request #1360 from filmaj/android-docs

Expanded Android docs
Fixed missing callback parameter
Merge pull request #1370 from bicycleio/master

Missing callback parameter causing Appium to crash
remove confusing multiple session handling code
it doesn't actually do anything and was cruft
also, make session overriding non-default based on the mobile
JSONWP discussions
check in midway through android startup/shutdown refactor
finish making shutdown() callback-based
command timeouts should be handled centrally by appium, not by each device
when we get an error starting up an android test, make sure we kill uiautomator
so it doesn't complain next time we run a test