The main entry point for all profile-related actions.

• Determines whether or not the user can access the section specified by the subaction based on permissions
• Passes output off to the appropriate function based on the sub-action or throws an error if the user can't access that section
• Loads up the member info for the specified user or the current member if no user is specified
• Accessed via ?action=profile[;u=someuser][;sa=subaction]
• Subaction can be one of the following: summary, statPanel, showPosts, trackUser, trackIP, showPermissions, account, forumProfile, theme, notification, pmprefs or deleteAccount
• In 1.1, if buddy lists are enabled, sub-action can also be editBuddies
• If no sub-action is specified, SMF picks the first one you're allowed to see (generally summary)
• Uses the profile template layer
• Sets up the profile menu items in $context['profile_areas'] based on permissions
• Keys in $post_errors indicate what error(s) occurred.