MDict: Add volumes support for mdd files
MDict: minor parser refactor, fix inappropriate use of sptr
Stardict: Isolate resources stylesheets
FFmpeg: Fix potential crash on some codecs (speex for example)
Dsl: Handle SVG images
Add "Copy Image" option into images context menu
Merge branch 'mdict'

Conflicts:
	mdx.cc
Fix unexpected result using QString::toStdWString() (fix #107 again, QTBUG-25536)

* QString::toStdWString() and QString::toUCS4() will have wrong size when
  QString instances contain non-BMP characters.

Close #320
lupdate all translations; update Simplified Chinese translation
Add an option to enable saving resource files with articles (#321)
Merge pull request #324 from timonwong/save_with_res

Add an option to enable saving resource files with articles (#321)
Update pt_BR.ts
Updated Brazilian Portuguese translation by Alexandro Casanova
Tweaks for background color since CSS isolation was introduced
MDict: Narrow selector scope for better CSS isolation (probably)
Fixed #328: Eliminate partially-checked checkboxes in Pereferences

This also eliminates the major problem on Xubunty 13.04 x64, when all those
partially checked checkboxes were without check marks at all.