Fix exponential increase of timeout when finding ancestor elements

The timeout passed to the "find" method was multiplied by the
"findTimeoutMultiplier" attribute. However, as "find" used
"findAncestor" and "findAncestor", in turn, used "find" itself the
timeout was increased exponentially for ancestor elements. Now "find"
was split in "find" and "findInternal"; the first method is the public
one and modifies the given parameters as needed and then calls the
second method, private, that performs the find itself.

Signed-off-by: Daniel Calviño Sánchez <danxuliu@gmail.com>