[Tolk] Completely rework stdlib: multiple files and renaming

- split stdlib.tolk into multiple files (tolk-stdlib/ folder)
  (the "core" common.tolk is auto-imported, the rest are
  needed to be explicitly imported like "@stdlib/tvm-dicts.tolk")
- all functions were renamed to long and clear names
- new naming is camelCase

tolk-tester/tests/a10.tolk

@@ -1,3 +1,5 @@
+fun pair_first<X, Y>(p: [X, Y]): X asm "FIRST";
+
 fun one(dummy: tuple) {
     return 1;
 }
@@ -30,6 +32,29 @@ fun test88(x: int) {
     }
 }
 
+@method_id(89)
+fun test89(last: int) {
+    var t: tuple = createEmptyTuple();
+    t~tuplePush(1);
+    t~tuplePush(2);
+    t~tuplePush(3);
+    t~tuplePush(last);
+    return (t.tupleAt(0), t.tupleAt(t.tupleSize() - 1), t.tupleFirst(), t.tupleLast());
+}
+
+@method_id(93)
+fun testStartBalanceCodegen1() {
+    var t = getMyOriginalBalanceWithExtraCurrencies();
+    var first = t.pair_first();
+    return first;
+}
+
+@method_id(94)
+fun testStartBalanceCodegen2() {
+    var first = getMyOriginalBalance();
+    return first;
+}
+
 /**
     method_id | in     | out
 @testcase |  0 | 101 15 | 100 1
@@ -39,4 +64,24 @@ fun test88(x: int) {
 @testcase |  0 | 100 10 | 100 0
 @testcase | 88 | 5      | 234
 @testcase | 88 | 50     | 0
+@testcase | 89 | 4      | 1 4 1 4
+
+
+@fif_codegen
+"""
+  testStartBalanceCodegen1 PROC:<{
+    //
+    BALANCE // t
+    FIRST	//  first
+  }>
+"""
+
+@fif_codegen
+"""
+  testStartBalanceCodegen2 PROC:<{
+    //
+    BALANCE
+    FIRST	//  first
+  }>
+"""
 */