Maxthon 3.4.2.600 Beta

# New Features:
* Supported saving pages as mht files in Ultra Mode
* Added tooltip when extensions successfully installed
* Reserved "Forward/Back " list and scroll bar position in Duplicate Tab
* Added auto update and syncing service of extensions
* Supported HTML5 color input

# Fixes:
* Main Frame
- Tool Bar display problem
- Icon display problem in Source Sniffer
* Webkit Core
- Some language characters display problem
- No response problem of the browser
- Some ads were displayed by mistake
- Page display problem
- Some error pages did not show completely
- Proxy identity authentication did not work well
* Extension Platform
- Right-click menu of extensions displayed errors
- Focus loss problem of extension windows