演讲标题随机选择器

简单随机从题库（文件夹）中抽取题目

Name		Name	Last commit message	Last commit date
Latest commit History 8 Commits
Properties		Properties
.gitattributes		.gitattributes
.gitignore		.gitignore
App.config		App.config
FormMain.Designer.cs		FormMain.Designer.cs
FormMain.cs		FormMain.cs
FormMain.resx		FormMain.resx
LectureSelector.csproj		LectureSelector.csproj
LectureSelector.sln		LectureSelector.sln
Program.cs		Program.cs
README.md		README.md
TemplateIcon.ico		TemplateIcon.ico

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