Added quote method for numbers
Removed unused imports
Quoted values in assertion error messages
Added attribute is number methods
Refactored code attribute methods + fixed attribute and text not contains bugs
Removed unused variable
Renamed tagIn and tagInWithoutHtml to htmlOf and htmlOfWithoutInnerHtml
Removed misplaced indentation
Refactored comment and new lines
Polished htmlOf and htmlOfWithoutInnerHtml
Added WebAssertionError
Refactored to use WebAssertionError exceptions + refactored assertion messages