为微软的文本转语音服务的 demo 页面添加下载按钮

收集模式：

打开之后，点击“下载”按钮转换的音频会被收集，在收集模式关闭时合成一个音频下载

自动拆分：

将长文本拆分为多个接近“段落长度”的片段，并只在“分隔符”处截断，避免句子被截断，影响阅读效果

多配置切换：

将当前语音设置储存为配置，点击快速切换


Add download button to the demo page of Microsoft's text to speech service

Collection：

Collect audio files converted by clicking "Download" button, do the really download when it is turned off

Split：

Split long text into segments close to the "paragraph length", which only truncate at "delimiter"

Multi profile switching:

Save the current voice settings as a profile, click to switch