added write capability

[b-r-y-a-n]

This is a bit unsolicited, so I don't know if you want to allow these things in your MCP, but I needed them, so I thought I'd contribute my fork back.

This adds some basic write capabilities including

• create a feature
• assign a user to a feature
• change status
• lookup statuses (so you can reference them by name when changing status and the agent can look up ids)
• assign release
• lookup releases (so you can reference releases by name and the agent can lookup the id for above)
• add feature comments