#306 String case sensitivity

[Alecsis]

I think it would be useful to add case-insensitive string comparison operation. In addition, extend InStr function with the same capability.
For example something like below:
If str1 = str2 Then [do smth] ' case insensitive "AbC" = ''abc"
If str1 == str2 Then [do smth] ' case sensitive "AbC" <> ''abc"