Dead Water Polish translation update

Dead Water Polish translation update, updates delivered by Wesbane.
Heir To The Throne: Polish translation update

Heir To The Throne: Polish translation update, updates delivered by Wesbane.
Legend of Wesmere Polish translation update

Legend of Wesmere: Polish translation update, updates delivered by Rafał.
The Rise of Wesnoth: Polish translation update

The Rise of Wesnoth: Polish translation update, updates delivered by Rafał.
Removed comments

Removed comments to trigger new build.
Two Brothers: Polish translation update

Two Brothers: Polish translation update, updates delivered by Wesbane.
Escape >= in pkg-config command in cross-platform way
Eastern Invasion: Polish translation update

Merged from master.
The Eastern Invasion, small update (pl)
Merge pull request #230 from aquileia/pl

Polish translation update
Merge pull request #232 from pjackowski/1.12

Eastern Invasion: Polish translation update (1.12)
fixup inefficient invisibility calculation for units

Units have a function with signature
bool unit::invisible(const map_location & loc, bool see_all)

which determines whether the unit, if it is invisible, would be
revealed if it were moved to map_location & loc.

The implementation of this function was needlessly inefficient, it
requires us to loop through the entire unit_map (all of the units)
to determine if any of them could ambush the unit.

However, in the course of this check, it filters out any units
whose location is not adjacent to the target location.

This function is called constantly whenever the display is updated
or the minimap is drawn, or when a unit is moved.

The improved implementation does not loop over all units, instead
it gets the list of (6) map locations which could be adjacent and
have a unit, and then queries for a unit at each of those
locations.
update changelog
Fix a memory leak in forum_user_handler
Fix memory leak in wesnothd
Add a comment explaining the use of boost::shared_ptr
Xcode project: add precompiled header file for release build

The current combination of SDKs and build targets for release builds
does not include sys/types.h automatically any more (while it does for
debug builds).
wmlindent pass on data/themes/
wmlindent pass on data/core/
wmlindent pass on data/campaigns/