add keywords:
* Page Should Contain Element
* Page Should Not Contain Element
replace keywords name "Page Should Contain" by "Page Should Contain Text"
replace keywords name "Page Should Not Contain" by "Page Should Not Contain Text"
update readme for mention support appium 1.x
add element_should_be_disabled and element_should_be_enabled keywords
add keyword element_name_should_be
display name if element name is not expected
1.0.10
Merge branch 'master' into gh-pages