Added optional reason to the ignore feature.

In multiplayer, this supports players to associate a reason with ignored users that is displayed with the ignored username. Resolves http://wiki.wesnoth.org/EasyCoding#Add_possibility_to_give_reason_for_.22ignore.22.
Added timestamps in Chatlog

It was a little odd that timestamps checkbox in Preferences affected
only regular chat messages, but not the chatlog, so I decided to add
timestamps into the chatlog.

I hate to use `const_cast` to add a timestamp to a received message, so
if someone knows a better solution, don't hesitate to mention it.
Improved friends storage system to store "acquaintances" as separate children.

The current attributes are status (either friend or ignore), the nickname, and any attached notes.
Refactoring unit class to use boost::scoped_ptr instead of raw pointer.

This change aims to simplify the code, making the intents more explicit.
There wasn't a memory leak in the previous version, but it could easily be
introduced in the future.

Also, RAII is part of the coding standards of Wesnoth, as noted in the wiki.

There are other raw pointers in the unit class, but unit don't own them, then
I leave them unchanged.
Don't need to escape the reason anymore with new storage system.
Added notes for friends.
Modified timestamps

Modified the previous commit after discussing it with Soliton. We agreed
on sending timestamps to other players and using them [received timestamps]
in displaying time of chat messages, with fallback on using local time if
received message doesn't contain timestamp (old version of wesnoth).

This fixes several issues:
1) When viewing replays the time would be the one of the actual game
insted of the time of viewing the replay;
2) Previously, when opening some dialog while players send messages and
then closing it — chat messages would have timestamp of when the dialog
windows was closed, not the time when messages were sent.

This also introduces one new issue:
1) If player has time set up incorrectly, the timestamp that other players
will recieve will show incorrect time.
For example, when instead of setting to the right timezone player just
adjusted system time by adding or subtracting hours with incorrect
timezone selected.
Refactoring

Renamed undescored variable so it won't get taken for class variable by
mistake.
Merge pull request #4 from nurupo/master

Added timestamps in Chatlog
Update changelog
We're not using svn anymore
Renamed the icons for the time switch action properly.
Time and Schedule selection in the editor.
Also replace '+svn' with '+dev' in wesconfig.h

Caught by anonymissimus
Added ability for Healer Support mai to avoid certain tiles based on standard ai avoid aspect.
Merge pull request #10 from jleldridge/master

Allow Healer Support MAI to use [avoid] aspect to avoid locations.
Update changelog
Set the color adjustment on schedule switch.
Images for the switch time action.
Updated artwork for sliders, including 2 new types of slider. All slider artwork is regrouped into the subfolder images/buttons/sliders