Removed duplicate error message output, and fixed bug with undefined error output.

When trying to run a program in the javascript compiler which throws a RuntimeException, such as:

import "cactus" as cactus

The output will contain two lines with the same message:

Error around line 1: RuntimeError: could not find module cactus
Error around line 1: RuntimeError: could not find module cactus

My fix in index.in.html fixes this.

---

When compiling a program that doesn't terminate in a newline, the last line of the program is not added to the lines or util.lines variable. This can result in error messages having undefined lines.

E.g. Take the program "print (x)" with no newline, the js compiler produces the following message:

main.grace:1:7: syntax error: use of undefined identifier x
  1: undefined
-----------^

And the c compiler doesn't print out the line at all, only saying:

main.grace:1:7: syntax error: use of undefined identifier x

With my fix in lexer.grace, both the javascript and c compilers produce the following output:

main.grace:1:7: syntax error: use of undefined identifier x
  1: print(x)
-----------^