[misc] pocketful of enhancement and fixes - part 4

* Fix disappearance of "Start" button when selecting an ISO with
  no target (reported by Sopor)
* Add commented sample ini file
* Add AC_PROG_AR macro in configure.ac
* Update ChangeLog for BETA

res/rufus.ini

@@ -0,0 +1,17 @@
+; The following is a sample INI file, as used by Rufus
+; Whenever Rufus detects a 'rufus.ini' in the directory you launched it from
+; (even an EMPTY ONE), it starts in portable mode, and store all its settings
+; there, instead of the Registry.
+; In most cases, you should never have to modify an INI file manually. But if
+; needed, the format of the 'rufus.ini' is documented hereafter:
+
+; The translation used by the Rufus to display its UI (RFC 1766)
+Locale = en-US
+; Internal, to confirm R/W access to these settings
+CommCheck = 20089578
+; Timestamp of the last update check
+LastUpdateCheck = 13068056756
+; Amount of time before Rufus checks for another update (in seconds)
+UpdateCheckInterval = 86400
+; Use this to increases the log verbosity, for the update checks
+VerboseUpdateCheck = 0