(svn r7205) -Fix [FS#350, SF#1560913]: Window allocation and deletion messed with the actual window
structs inside their array, and possibly invalidating pointers higher up.
Meaning that any function called within an wndproc could cause unknown/invalid pointers
once control was returned to this function. Solved by the introduction of an extra
abstraction layer, an array of z-window positions that is only concerned with the
pointers.

(svn r3564) Several smaller changes:
- Don't treat non-booleans as booleans
- Reduce variable scope
- Bracing
- Use DeMorgan's law to make conditionals easier to read
- if cascade -> switch
- Replace some magic numbers by symbolic names
- Avoid assignments within other statements

(svn r1637) -Fix: VS6 warning
-Added missing files to VS6 and VS.Net project files (bociusz)

(svn r513) Merge revisions 402, 416, 417, 478, 479, 511, 512 from map to trunk
This includes 2 fixes
-Fix: [1048596] Monorail and Maglev sounds are swapped (r511)
-Add special case to load the jackhammer sound (r478)
The rest are cleanups und enumeration to make merging possible/easier