修复version长短选项都被清除时help信息输出错误的问题 (#107)

* 优化usage显示信息

* 更新版本信息显示功能，去除进程名显示

* 更新测试用例

* 调整about信息显示

* 调整about显示模板

* 输出版本号时增加换行

* 调整版本功能

* 修复version长短选项都被清除时help信息输出错误的问题

clop.go

@@ -661,7 +661,7 @@ func (c *Clop) genHelpMessage(h *Help) {
 			c.shortAndLong[c.versionShort()] = &Option{usage: "print version information", showShort: []string{c.versionShort()}, showLong: []string{c.versionLong()}}
 		} else if c.versionShort() != "" {
 			c.shortAndLong[c.versionShort()] = &Option{usage: "print version information", showShort: []string{c.versionShort()}}
-		} else {
+		} else if c.versionLong() != "" {
 			c.shortAndLong[c.versionLong()] = &Option{usage: "print version information", showLong: []string{c.versionLong()}}
 		}
 	}