support setting wait time in Waiter instead of using Capybara.using_wait_time
add set_time test in waiter_test
Merge pull request #77 from appfolio/setWaitTimeInWaiter

Support setting wait time in Waiter instead of using Capybara.using_wait_time
Added ElementProxy#wait_for_absence
Added ElementProxy#wait_for_presence
Accept a timeout parameter to the ElementProxy#wait_for_* methods.
Addressing code review comments.
Merge pull request #78 from appfolio/fixElementProxyNotPresent

ElementProxy enhancements and fix for #65
Update WindowHandleManager.current to handle NoSuchWindowError