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.
Eastern Invasion: Polish translation update

Eastern Invasion: 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.
remove unnecessary include
move SDL threading includes out of header
remove unnecessary include
fix servergenerated replays

if this is a reloaded game then we dont need to add [start]
remove code duplication of unit advancements

the advancemnts after [unstore_unit] and after attacks now use the same
function.
Rewrite some logic so C++11 considers it a boolean context
Special-case si_string(0) so we don't get 0.0 yocto-whatever
added test checks in intrusive_ptr_add_ref/release
Merge branch 'master' of github.com:wesnoth/wesnoth
Fix OpenMP compilation

Delete a #pragma that tries to paralellize a BOOST_FOREACH loop. This
doesn't work as boost inserts lines before the for, thus hindering the
compiler to find the 'for'.
Fix VC project files
add unit drawer, remove drawable_unit

This avoids the casting to superclass, and it's also a bit faster,
in the refactor of the redraw_unit function we cache all the values
from display that we need locally.
fixup: initialize ref_count_ to 0 in units
Merge branch 'master' of git://github.com/wesnoth/wesnoth