Add hook documentation to bp-friends-classes.php.

Props tw2113.
Fixes #5942.

git-svn-id: https://buddypress.svn.wordpress.org/trunk@9206 cdf35c40-ae34-48e0-9cc9-0c9da1808c22
Add some hook documentation for the Messages component.

Props tw2113.
See #5945.

git-svn-id: https://buddypress.svn.wordpress.org/trunk@9207 cdf35c40-ae34-48e0-9cc9-0c9da1808c22
Assemble message notification filters dynamically.

This allows us to centralize the documentation.

Props tw2113.
See #5970.

git-svn-id: https://buddypress.svn.wordpress.org/trunk@9208 cdf35c40-ae34-48e0-9cc9-0c9da1808c22
In `bp_has_notifications()` test, declare `$user_id` explicitly.

git-svn-id: https://buddypress.svn.wordpress.org/trunk@9209 cdf35c40-ae34-48e0-9cc9-0c9da1808c22
Introduce Member Types API.

BuddyPress member types are akin to WordPress's custom post types. Developers
can use `bp_register_member_type()` to register their types with BuddyPress,
and BP will automatically provide a number of pieces of functionality:

* Mechanisms for storing and fetching member types (as a WP taxonomy term), with full cache support.
* A 'member_type' argument for the `bp_has_members()`/`BP_User_Query` stack, which allows filtering member loops by member type.
* Admin UI for changing member types on Dashboard > Users > Community Profile (appears when member types have been registered).

We'll continue to build out more core member type functionality in future
versions of BuddyPress. In the meantime, this is a good starting point for BP
site implementations to have a shared infrastructure for storing and retrieving
this data.

See #6006.

git-svn-id: https://buddypress.svn.wordpress.org/trunk@9210 cdf35c40-ae34-48e0-9cc9-0c9da1808c22
Better regex for parsing member type taxonomy SQL in WP < 4.1.

See #6006.

git-svn-id: https://buddypress.svn.wordpress.org/trunk@9211 cdf35c40-ae34-48e0-9cc9-0c9da1808c22
Activity: when generating RSS output, send a HTTP header to disable content type sniffing.

Since we're sending a correct Content-Type header, we don't want browsers to misinterpret the data we're sending.

git-svn-id: https://buddypress.svn.wordpress.org/trunk@9212 cdf35c40-ae34-48e0-9cc9-0c9da1808c22
Don't use `extract()` in `BP_Activity_Activity::get()`.

Props r-a-y.
See #5698, #4988.

git-svn-id: https://buddypress.svn.wordpress.org/trunk@9213 cdf35c40-ae34-48e0-9cc9-0c9da1808c22
Fix @since tag to match 3-digit BuddyPress standard.

See #5945.


git-svn-id: https://buddypress.svn.wordpress.org/trunk@9214 cdf35c40-ae34-48e0-9cc9-0c9da1808c22
Add hook documentation for the Settings component.

Fixes #5947


git-svn-id: https://buddypress.svn.wordpress.org/trunk@9215 cdf35c40-ae34-48e0-9cc9-0c9da1808c22
Add hook documentation for the Messages component.

Fixes #5945


git-svn-id: https://buddypress.svn.wordpress.org/trunk@9216 cdf35c40-ae34-48e0-9cc9-0c9da1808c22
Missed blank line above filter docblock.

See #5945 


git-svn-id: https://buddypress.svn.wordpress.org/trunk@9217 cdf35c40-ae34-48e0-9cc9-0c9da1808c22