学习Wordpress插件中，出现PHP错误告警信息：
Cannot modify header information – headers already sent by ……
参考下面的文章，使用工具去除PHP代码中的BOM，问题解决。
Refer to:
Cannot modify header information – headers already sent by错误解决办法
Refer to: http://wordpress.org/extend/plugins/about/
第一步：注册插件开发的账号
http://wordpress.org/extend/plugins/register.php
注：该账号可以开发和提交插件和主题。
第二步：提交插件申请
http://wordpress.org/extend/plugins/add/
注：因为是人工审批，一般提交后1到2天才能完成。
第三步：提交插件
任务1：提交新的插件
# 创建插件目录
$ mkdir my-local-dir
# Check out 版本
$ svn co http://svn.wp-plugins.org/your-plugin-name my-local-dir
# 复制插件文件
$ cd my-local-dir/
my-local-dir/$ cp ~/my-plugin.php trunk/my-plugin.php
my-local-dir/$ cp ~/readme.txt trunk/readme.txt
# 添加文件到版本
my-local-dir/$ svn add trunk/*
> A trunk/my-plugin.php
> A trunk/readme.txt
# Check in 版本
my-local-dir/$ svn ci -m ‘Adding first version of my plugin’
> Adding trunk/my-plugin.php
> Adding trunk/readme.txt
> Transmitting file data .
> Committed revision 11326.
任务2：修改插件
# 更新本地版本
$ cd my-local-dir/
my-local-dir/$ svn up
> At revision 11326.
# 修改本地插件
my-local-dir/$ vi trunk/my-plugin.php
# 检查哪些文件修改过
my-local-dir/$ svn stat
> M trunk/my-plugin.php
# 检查文件修改的内容
my-local-dir/$ svn diff
> * What comes out is essentially the result of a
* standard `diff -u` between your local copy and the
* original copy you downloaded.
# Check in 版本
my-local-dir/$ svn ci -m “fancy new feature: now you can foo *and* bar at the same time”
> Sending trunk/my-plugin.php
> Transmitting file data .
> Committed revision 11327.
任务3：标记新版本
# 复制最新的文件到到新版本目录
my-local-dir/$ svn cp trunk tags/2.0
> A tags/2.0
# Check in 新版本目录
my-local-dir/$ svn ci -m “tagging version 2.0″
> Adding tags/2.0
> Adding tags/2.0/my-plugin.php
> Adding tags/2.0/readme.txt
> Committed revision 11328.
注：如果只需要保存最新版本，可以省略这个步骤。
SVN链接和具体操作步骤：
Wordpress plugin SVN Link: http://plugins.svn.wordpress.org/XXX/
Wordpress plugin SVN Howto: http://wordpress.org/extend/plugins/about/svn/
插件的说明文件需要符合标准：
FAQ: http://wordpress.org/extend/plugins/about/faq/
readme.txt standard: http://wordpress.org/extend/plugins/about/readme.txt
readme.txt validator:: http://wordpress.org/extend/plugins/about/validator/
注：XXX就是提交的插件名称；官网上提供插件说明文件的验证。
