Maxthon 2.5.12.4456 Beta

# Safety
+ added new interface for Privacy Mode
* fixed problem that safe box dialog may be shown incorrectly
* fixed problem that external links cannot be opened in Privacy Mode
* improved notice for malicious websites

# Interface
* fixed problem that Mute Browser button state may not correspond to actual state
* fixed problem that browser may not switch to background tab

# Browsing
* fixed problem that external links may not be opened
* fixed problem that opening https websites may crash

# Passport
* fixed an auto login problem

# Float Button
* fixed some possible crash problems

# Others
* fixed a browser settings lost problem