Add ExtractAttachFile Method (no use)
Add ExtractMessage and Update NET4.5.
Merge branch 'develop' into Split

Conflicts:
	AkaneMail/AkaneMail/MainForm.Designer.cs
	AkaneMail/AkaneMail/MainForm.cs
	AkaneMail/AkaneMail/MainForm.resx
	AkaneMail/AkaneMail/Properties/Resources.Designer.cs
	AkaneMail/AkaneMail/Properties/Settings.Designer.cs