update underlying code to automatically convert types

[MajeedKazemi]

for Scratch:

• the mathematical operators --- + --- should convert both operands to integers by default, and catch any errors (because of parsing)
• similarly, join --- and --- should convert both operands to string

[user-74]

Note: the + operator still has issue putting in text, check where type checking is for this and allow it

[user-74]

Solved in code generation by applying parseInt() wherever needed