fix: include final character in line lenght

Before, wrapping the help text at, say, 80 characters really meant
that every line could be at most 79 characters wide.

Lines can now be up to and including avail_chars columns wide.

If needed, a desired margin or padding can be subtracted from the
avail_chars argument at a later point.

Author: mgeisler

src/app/help.rs

@@ -948,7 +948,7 @@ fn wrap_help(help: &mut String, longest_w: usize, avail_chars: usize) {
                     continue;
                 }
                 debugln!("Help::wrap_help:iter: Reached the end of the line and we're over...");
-            } else if str_width(&help[j..idx]) < avail_chars {
+            } else if str_width(&help[j..idx]) <= avail_chars {
                 debugln!("Help::wrap_help:iter: Space found with room...");
                 prev_space = idx;
                 continue;

tests/help.rs

@@ -113,9 +113,8 @@ OPTIONS:
                          latte, cappuccino, espresso), tea, and other
                          hot beverages. Some coffeehouses also serve
                          cold beverages such as iced coffee and iced
-                         tea. Many cafés also serve some type of
-                         food, such as light snacks, muffins, or
-                         pastries.";
+                         tea. Many cafés also serve some type of food,
+                         such as light snacks, muffins, or pastries.";
 
 static ISSUE_626_PANIC: &'static str = "ctest 0.1
 
@@ -514,4 +513,4 @@ fn issue_777_wrap_all_things() {
         .about("Show how the about text is not wrapped")
         .set_term_width(35);
     assert!(test::compare_output(app, "ctest --help", ISSUE_777, false));
-}
+}