Set minimal acceptable Qt4 version to 4.3.0

Nicer look

Iconize more groupboxes

Finish iconed groupbox implementation

Add iconed groupbox class

With this change, SDL will probably report more screen resolutions on dual-monitor configurations

Enable back rendering objects that are put on top of land texture

Fix compile under Ubuntu (why it compiles everywhere else?)

Fix installation path for Castle map

Convert the rest of themes too

Step 5: Finally... we have theme objects with alpha-channel! Only nature theme converted yet, others in the next commit

- Fix previous commit - Code formatting in uStore

Allow theme-customizable water and girder

Step 4: repair girder rendering (girder is 32bit now)

Step 3: Maps are rendered correctly, but without objects yet

Step 2: painted maps loading correctly

Start implementing support for 32bit sprites concerned in map generation process. Step 1: forts are loading correctly. Everything else is broken

This needs to be changed too

- Fix Qt's runtime warning - This fix probably eliminates network problems

Add "Castle" map copyright info

Disallow AI to hurts itself with mortar (in quite rare cases it tries to shoot directly up)

Update frontend background

Oops, fix map install path

Revert accidental nsis installer generator regression