qt: Use QImage instead of QImageReader to load mouse cursor images.

Some combination of QImageReader, QImage, QPixmap, QCursor and the wzfs wz:: virtual file system apparently doesn't
work in Qt 4.8.2 (but works in Qt 4.8.1).

The following error was printed (multiple times) to the shell:
QCursor: Cannot create bitmap cursor; invalid bitmap(s)

Fixes ticket:3562.
Do not use std::string in a memory structure that is memset().
Patch by tnmurphy, closes ticket:3620
Update nullbot to latest version. Rename nullbot include files to avoid spurious qslint errors.
Update the changelog
Use codesigning for the mac builds.

Requires the presence of 'macosx/configs/CS-ID.xcconfig' containing a valid codesign id listed in a CODE_SIGN_IDENTITY property.
Make improvements to the case where there is no codesign id.
Remove unused lines of code from display.cpp
Merge branch 'bugfixes' of github.com:Warzone2100/warzone2100 into bugfixes
No longer save default map, max players and map hash. Patch originally by vexed. Closes ticket:3618
Assert on collision of hashes of resource types or filenames.

This should be a minor improvement over silently retreiving the wrong resource on filename hash collisions.
Correctly handle interface image texture pages which are not 256x256.

Game logo now appears full size.
Split frontend*.png and intfac*.png into individual images.

The images are now combined into texture pages at runtime.

This should simplify adding/removing images.
Warn when uplink and/or lassat is disabled.
Add header for std::sort.
Add files missing from 1e5fafabb39f76762ab7a560be7770595bc60a8c.

Fixes ticket:3646.
Fix missing decals in Rocky Mountains tileset that were specially made for it
but never mentioned in the rockiedecals.txt file. It also fixes the ground
types of certain urban and rocky tiles to resemble the old 2.3 terrain more
exactly. Patch by NoQ. Closes ticket:3621
Update ChangeLog
Revert "Fix reported [-Werror=format] issue."

This reverts commit 0bfee185a38c1a354c14b33a064d13d81a03962f.
Revert "Add last part of net patch (needs updated server code)."

This reverts commit 329572779ae2e383b6bd668078ee4ecffe173dc4.
Use std::multiset::iterator instead of std::set::iterator with std::multiset.

Apparently, the iterators were compatible, in some library implementations.