(svn r12867) [0.6] -Backport from trunk r12706, r12642, r12622, r12572, r12542:
- Fix: Do not crash very hard on unrecognised savegames, just go back to the intro menu instead (r12706)
- Fix: Remove buggy buoys at tile 0 from old TTDP savegames (r12642)
- Fix: Infinite loop in case your compiler decides that enums are unsigned by default (r12622)
- Fix: min() has 32bit arguments, clamping of 64bit values did not work (r12572)
- Fix: Do not install scenarios into the current user's homedir when running 'make install', that is silly. Simply always install scenarios system wide instead (r12542)

Makefile*
bin/*
!bin/data/chars.grf
!bin/data/openttdd.grf
!bin/data/openttdw.grf
!bin/data/opntitle.grf
!bin/scenario/README
!bin/scripts*
config.*
objs/*
src/rev.cpp