URL for bbp_get_reply_to_link() is wrong

[GDragoN]

Function bbp_get_reply_to_link() should generate Reply To link for a reply, but the generated URL is valid only inside the topic thread. For Reply inside User Profile Replies Created page, the URL is wrong.

This function doesn't really generate the URL, it just adds the query argument to existing URL, whatever that may be. This function needs first to get URL to the topic before adding the arguments.

[GDragoN]

Patch for the issue.