escape single quotes in optioninput (optionresponse) tags

STUD-893

@cahrens @adampalay @singingwolfboy 
Escape single quotes in options (optionresponse) with or without leading backslash.
Note: Only those single quotes will be escaped which are in between two alphabets.
```
<optioninput options="('hasnot','hasn't','has'nt')" correct="hasn't"></optioninput>
```
To escape single quotes in between unicode characters or inside option manually use leading backslash.
```
<optioninput options="('кавыки','кавы\'ки')" correct="кавы'ки"></optioninput>
```
Note:
1) Option (inside optioninput) with two double quotes ```"hasn't"``` won't work because it will make problem html invalid.
2) Correct option don't need leading backslash because it is a separate single attribute and don't parse during problem save/check. So if Correct option is ```"hasn't"``` then both ```'hasn't'``` or ```'hasn\'t'``` will be valid but not vice versa.
3) Correct option cannot be inside single quote (`'hasn't'`) as it will make problem content invalid. so double or single quotes matter, in both the listing of the answer choices and the specification of the correct answer.