Fix usage of the explicit keyword.
Remove unused private members.
Remove unused private members.
Remove unused private members.

Also removes the now unused SPACE_CONSUMPTION enum.
Remove a useless cast.
Remove a useless cast.
Remove a useless cast.
Disable null conversion warning in CMake.

It gives problems when using Clang and boost::shared_ptr when compiling
for C++11. The issue can't be fixed since Wesnoth uses C++98. (So we use
NULL instead of nullptr.)
Use a const reference instead of a const pointer.

The argument is mandatory, so use a reference.
AI/lua: Command 'lua wesnoth.debug_ai(2).ai' gives now access to ai-table
Use a reference instead of a pointer.

The argument is mandatory, so use a reference.

This changes the callbacks of the GUI, thus causing several changes in
all users of the callbacks.
Use a reference instead of a pointer.

The argument is mandatory, so use a reference.

This updates get_parent.
Rename gui2::twidget::dirty to is_dirty.

Also updates the setter and getter members of gui2::twidget.
Rename gui2::tcanvas::dirty to is_dirty.

Also updates the setter and getter members of gui2::canvas.
Remove the default argument of set_is_dirty.
Add new aspect 'advancements'

As part of a GSoC proposal I added a new aspect so a scenario editor can control advancements in two ways:
1. Define a aspect with a string-value like "Swordsman, Knight", so the units of interesst will always advance to this
2. Use the LUA-Engine and return a function of the form advance(x, y) which will itself return a string-value
    like "Swordsman, Knight". Everytime a ai-unit advances advance(x, y) will be called.
The corresponding wikipage (http://wiki.wesnoth.org/AiWML) is going to be updated soon.
Merge branch 'gui_polishing'
Remove a variable which is only assigned.

Issue found by cppcheck.
Add comments to data/ai/formula/new_recruitment.fai
remove files on Windows so --revert and second conversions can proceed

Windows won't allow a rename to overwrite an existing file (Error 183, file already exists).