Allow using expanded macro without loading feature

In the macro `use-package-with-elapased-timer' use `bound-and-true-p'
go get the values of the customizable options `use-package-verbose'
and `use-package-minimum-reported-time'.  This way the library only
has to be required at compile time, provided these options are not
actually customized.  If the user has changed the values, then she
also has to load the library at runtime or the macros fall back to
the default of doing their job silently.  See jwiegley/use-package#149.

lisp/use-package/use-package.el

@@ -48,12 +48,27 @@
   :group 'startup)
 
 (defcustom use-package-verbose nil
-  "Whether to report about loading and configuration details."
+  "Whether to report about loading and configuration details.
+
+If you customize this, then you should require the `use-package'
+feature in files that use one of the macros `use-package' or
+`use-package-with-elapsed-timer', even if these files only
+contain compiled expansions of the macros.  If you don't do so,
+then the expanded macros do their job silently."
   :type 'boolean
   :group 'use-package)
 
 (defcustom use-package-minimum-reported-time 0.01
-  "Minimal load time that will be reported"
+  "Minimal load time that will be reported.
+
+Note that `use-package-verbose' has to be set to t, for anything
+to be reported at all.
+
+If you customize this, then you should require the `use-package'
+feature in files that use one of the macros `use-package' or
+`use-package-with-elapsed-timer', even if these files only
+contain compiled expansions of the macros.  If you don't do so,
+then the expanded macros do their job silently."
   :type 'number
   :group 'use-package)
 
@@ -65,13 +80,15 @@
 (defmacro use-package-with-elapsed-timer (text &rest body)
   (declare (indent 1))
   (let ((nowvar (make-symbol "now")))
-    `(if use-package-verbose
+    `(if (bound-and-true-p use-package-verbose)
          (let ((,nowvar (current-time)))
            (message "%s..." ,text)
            (prog1 (progn ,@body)
              (let ((elapsed
                     (float-time (time-subtract (current-time) ,nowvar))))
-               (if (> elapsed ,use-package-minimum-reported-time)
+               (if (> elapsed
+                      (or (bound-and-true-p use-package-minimum-reported-time)
+                          "0.01"))
                    (message "%s...done (%.3fs)" ,text elapsed)
                  (message "%s...done" ,text)))))
        ,@body)))