Retry operator argument semantics fix (#362)

* Fix retry operator's argument semantics

* Rephrase comments in tries parameter desc

Author: elelel

Rx/v2/src/rxcpp/operators/rx-retry.hpp

@@ -8,7 +8,7 @@
 
     \tparam Count the type of the counter (optional)
 
-    \param t  the number of retries (optional) If not specified, infinitely retries the source observable. Specifying returns immediately without subscribing
+    \param t  the total number of tries (optional), i.e. retry(2) means one normal try, before an error occurs, and one retry. If not specified, infinitely retries the source observable. Specifying 0 returns immediately without subscribing
 
     \return  An observable that mirrors the source observable, resubscribing to it if it calls on_error up to a specified number of retries.
 
@@ -100,7 +100,6 @@ namespace retry {
     struct values {
       values(source_type s, count_type t)
         : source(std::move(s)), remaining_(std::move(t)) {
-        if (remaining_ != 0) ++remaining_;
       }
 
       inline bool completed_predicate() const {

Rx/v2/test/operators/retry.cpp

@@ -119,7 +119,7 @@ SCENARIO("retry 0, basic test", "[retry][operators]") {
 
 
 SCENARIO("retry with failure", "[retry][operators]") {
-    GIVEN("hot observable of 3x4x7 ints with errors inbetween the groups. Retry 1. Must fail.") {
+    GIVEN("hot observable of 3x4x7 ints with errors inbetween the groups. Retry 2. Must fail.") {
         auto sc = rxsc::make_test();
         auto w = sc.create_worker();
         const rxsc::test::messages<int> on;
@@ -145,12 +145,12 @@ SCENARIO("retry with failure", "[retry][operators]") {
             on.completed(725)
         });
 
-        WHEN("retry of 1 is launched with expected error before complete") {
+        WHEN("retry of 2 is launched with expected error before complete") {
 
             auto res = w.start(
                 [&]() {
                 return xs
-                    .retry(1)
+                    .retry(2)
                     // forget type to workaround lambda deduction bug on msvc 2013
                     .as_dynamic();
             });