Allow shared examples to be called in tabular examples

[acant]

This will just improve the syntax for using shared examples, in tabular form. Here are some possible method options:

# option 1
inputs                            :arg1,   :arg2
it_behaves_like_with 'behaviour', :value1, :value2

# option 2
inputs 'behaviour',  :arg1,   :arg2
it_behaves_like_with :value1, :value2

# option 3
# Could we automatically detected a shared example?
inputs               :arg1,   :arg2
it_behaves_like_with :value1, :value2