Adding more concise matchers support

[plouc]

For now we have a pretty verbose way to express assertions to be made on complex objects, like this:

And json response should match
    | field | matcher | value     |
    | id    | contain | 123       |
    | name  | equal   | John      |
    | corp  | match   | ^(.+)ing$ |

I think we could provide the ability to use shorter notation, like this:

And json response should match
    | id *= 123         |
    | name = John       |
    | corp ~= ^(.+)ing$ |

Here is my proposal to do so (heavily inspired by CSS attribute selectors):

matcher	operator
equals	=
match regexp	~=
contains	*=
ends with	$=
starts with	^=

[plouc]

ping @bnadim, @aticus7886, what do you think?

[bnadim]

why not it's easier to read :)