hidePasswords, preferences, UI improvements.

[ADDED]     hidePasswords to Mac app for hiding the passwords in the large passwords display, hold alt to reveal.
[ADDED]     Way to easily open the Mac app's preferences.
[IMPROVED]  Use transparent main window to improve the blur effect.
[ADDED]     Key equivalent coach marks when holding alt.
[FIXED]     Don't change sites table when site text field loses focus.

Site/2013-05/index.html

@@ -118,7 +118,7 @@
                 <p>Master Password comes with a variety of built-in password types.  These types make your site's password look different, become more secure or more compatible with a site's password policy.</p>
                 <p>The default password is a great balance between security, compatibility and convenience.  It is designed to provide great entropy (security) whilst still being easy to manually enter or remember if needed.</p>
                 <p>You can generate a more secure password, or switch it to a PIN type to use for your bank card or cell phone's SIM lock.</p>
-                <p>Master Password also implements a hybrid solution allowing you to save custom passwords in the app.  These passwords are AES encrypted using a large 64-byte key derived from your master password.  This grants people who are forced to use a certain password (eg. by their systems administrators) a maximally secure solution given their situational constraints.</p>
+                <p>Master Password also implements a hybrid solution allowing you to save custom passwords in the app.  These passwords are AES encrypted using a large key derived from your master password.  This grants people who are forced to use a certain password (eg. by their systems administrators) a maximally secure solution given their situational constraints.</p>
             </div>
         
         </div></section>