rewrite smarter people's euler solutions

examples/puzzles/euler_16.zr

@@ -0,0 +1,19 @@
+func main[] : i64
+    let n: array = []
+    array.push(n, 1)
+
+    for j in 0..1000
+        let carry: i64 = 0
+        for i in 0..array.size(n)
+            let tmp: i64 = array.nth(n, i) * 2 + carry
+            array.set(n, i, tmp % 10)
+            carry = tmp / 10
+        while carry > 0
+            array.push(n, carry % 10)
+            carry = carry / 10
+    
+    let sum: i64 = 0
+    for i in 0..array.size(n)
+        sum = sum + array.nth(n, i)
+
+    io.println_i64(sum)