(svn r8430) -Fix

Replace the rather obscure control flow for handling aircraft/ship/train orders by something remotly comprehensible (see r3584)

(svn r8393) -Fix

-Codechange: CheckCompatibleRail() is only called for tiles which are known to contain a piece of rail. Simplify the function accordingly by eliminating unnecessary checks.
-Fix (?): Also fix an inconsistency in deciding what a compatible rail type is between level crossings and other rail tiles. It is unknown if this caused any problems.

(svn r8385) -Fix

-Regression (r8314): I only did half the necessary changes to move railtype from Engine to RailVehicleInfo. Now do the rest.

(svn r8320) -Fix

Simplify TrainPowerChanged() somewhat by eleminating code duplication

(svn r8276) -Fix

Change the signature of Swap() to be less error prone, i.e. pass the variables to be swapped by reference instead of passing pointers to the variables.
Just do Swap(x, y) instead of Swap(&x, &y). This prevents accidents when the variables are pointers.

(svn r8128) -Codechange: Split sprite and palette remap into separate 32 bit values.
This lets us increase the sprite width from 14 to up to 29 bits,
effectively nulling the old sprite limit. Table changes in next commit.