Wrong error messages when calling numerical operators on different types

[jcubic]

It seems that are some inconstancy in typechecking:

lips> (= "xx" 10)
You can't create LNumber from string

Wrong error message probably the function don't check types so error came from LNumber.

lips> (+ 1 "x")
Expecting number, got string

Missing in expression `+`

Another not related issue is that "Error" is missing in REPL.

[jcubic]

It will be hard to add ``in expression `+``` because operation are generic higher order functions. The rest of the issue was fixed.