imp: options that use require_equals(true) now display the equals s…

…ign in help messages, usage strings, and errors"

Closes #903

src/app/help.rs

@@ -283,7 +283,13 @@ impl<'a> Help<'a> {
                 }
                 try!(color!(self, "--{}", l, good))
             }
-            try!(write!(self.writer, " "));
+
+            let sep = if arg.is_set(ArgSettings::RequireEquals) {
+                "="
+            } else {
+                " "
+            };
+            try!(write!(self.writer, "{}", sep));
         } else if let Some(l) = arg.long() {
             if arg.short().is_some() {
                 try!(write!(self.writer, ", "));

src/args/arg_builder/option.rs

@@ -50,11 +50,16 @@ impl<'n, 'e> From<Arg<'n, 'e>> for OptBuilder<'n, 'e> {
 impl<'n, 'e> Display for OptBuilder<'n, 'e> {
     fn fmt(&self, f: &mut Formatter) -> Result {
         debugln!("OptBuilder::fmt");
+        let sep = if self.b.is_set(ArgSettings::RequireEquals) {
+            "="
+        } else {
+            " "
+        };
         // Write the name such --long or -l
         if let Some(l) = self.s.long {
-            try!(write!(f, "--{} ", l));
+            try!(write!(f, "--{}{}", l, sep));
         } else {
-            try!(write!(f, "-{} ", self.s.short.unwrap()));
+            try!(write!(f, "-{}{}", self.s.short.unwrap(), sep));
         }
 
         // Write the values such as <name1> <name2>