[FEATURE] add support for DOM tree relevant assertions made with strikt

[skrapeit]

skrape{it} should support well-known assertion libraries by adding custom matchers that are relevant when expecting things in the DOM tree. Strikt is an well-known and nicely extendable assertion library we want to support.

Please add the following custom matchers that can be used on Element objects

• isPresent
• isNotPresent
• isPresentTimes(n)
• hasText("")
• hasTextContainig("")
• hasTextStartingWith("")
• hasTextEndingWith("")
• hasClass("")
• hasClassContainig("")
• hasClassStartingWith("")
• hasClassEndingWith("")
• hasAttribute("" to "")
• hasId("")
• hasIdContainig("")
• hasIdStartingWith("")
• hasIdEndingWith("")
• isDisabled
  • check if element has attribute disabled
• hasSrc("")
• hasSrcContaining("")
• hasSrcStartingWith("")
• hasSrcEndingWith("")
• hasTitle("")
• hasTitleContainig("")
• hasTitleStartingWith("")
• hasTitleEndingWith("")
• hasHref("")
• hasHrefContainig("")
• hasHrefStartingWith("")
• hasHrefEndingWith("")