Get Text succeeds and returns None if the element is not found instead of failing

[ombre42]

Execute: ${text} Get Text id=doesNotExist

Expected: fails with error similar to other keywords such as
ValueError: Element 'id=doesNotExist' not found.
or
ValueError: Element locator 'id=doesNotExist' did not match any elements.

Actual: keyword succeeds and ${text} is assigned a value of None

This appears to be the same root cause as Issue #114 - _ElementKeywords._get_text() returns None if the element is not found instead of raising an exception

[emanlove]

'Get Text' and 'Element Should Contain' now throws exception if element is not found. See #127.

[ombre42]

This was fixed in 1.1. The error as implemented looks like this:
ValueError: Element locator 'id=doesNotExist' did not match any elements.