Fix matching of case-instensitive literals

Code that calculated which part of the input to match against a literal
was wrong in case of case-insensitive literals when generating
speed-optimized parsers. As a result, matching of case-insensitive
literals worked only at the end of the input (where too big length
passed to the |substr| method didn't matter).

Fixes GH-153.

lib/compiler/passes/generate-javascript.js

@@ -546,7 +546,7 @@ module.exports = function(ast, options) {
           case op.MATCH_STRING_IC:  // MATCH_STRING_IC s, a, f, ...
             compileCondition(
               'input.substr(peg$currPos, '
-                + ast.consts[bc[ip + 1]].length
+                + eval(ast.consts[bc[ip + 1]]).length
                 + ').toLowerCase() === '
                 + c(bc[ip + 1]),
               1