Add crashes and fixes found during fuzzy testing

* Let unhandled exceptions propogate to user
 * Report eval_error when break statement is not in loop
 * Fix handling of 0 length scripts closes #193
 * Don't crash on arity mismatch - Specifically affects the case where no overloads exist for a given function
 * Fix error printing for `bind` calls
 * Handle unexpected continue statement
 * Check arity during bind
 * Don't allow arith conversion on variadic function
 * Correct `bind` parameter match count
 * Add in expected Boxed_Value exception cases
 * Check access to AST, don't allow `;` in func def
 * Don't attempt arithmetic unary & call
 * Don't crash on 0 param call to `bind`
 * Catch errors during member function dispatch
 * Properly handle type of const bool &

include/chaiscript/dispatchkit/bootstrap.hpp

@@ -304,13 +304,17 @@ namespace chaiscript
       /// the remaining parameters are the args to bind into the result
       static Boxed_Value bind_function(const std::vector<Boxed_Value> &params)
       {
-        if (params.size() < 2)
-        {
-          throw exception::arity_error(static_cast<int>(params.size()), 2);
+        if (params.empty()) {
+          throw exception::arity_error(0, 1);
         }
 
         Const_Proxy_Function f = boxed_cast<Const_Proxy_Function>(params[0]);
 
+        if (f->get_arity() != -1 && size_t(f->get_arity()) != params.size() - 1)
+        {
+          throw exception::arity_error(static_cast<int>(params.size()), f->get_arity());
+        }
+
         return Boxed_Value(Const_Proxy_Function(std::make_shared<dispatch::Bound_Function>(std::move(f),
           std::vector<Boxed_Value>(params.begin() + 1, params.end()))));
       }