Feature: auto-detect map height limit based on generated map

This opens up the true power of the TGP terrain generator, as it
is no longer constrainted by an arbitrary low map height limit,
especially for extreme terrain types.

In other words: on a 1kx1k map with "Alpinist" terrain type, the
map is now really hilly with default settings.

People can still manually limit the map height if they so wish,
and after the terrain generation the limit is stored in the
savegame as if the user set it.

Cheats still allow you to change this value.

(svn r7759) -Merge: makefile rewrite. This merge features:
- A proper ./configure, so everything needs to be configured only once, not for every make.
- Usage of makedepend when available. This greatly reduces the time needed for generating the dependencies.
- A generator for all project files. There is a single file with sources, which is used to generate Makefiles and the project files for MSVC.
- Proper support for OSX universal binaries.
- Object files for non-MSVC compiles are also placed in separate directories, making is faster to switch between debug and release compiles and it does not touch the directory with the source files.
- Functionality to make a bundle of all needed files for for example a nightly or distribution of a binary with all needed GRFs and language files.

Note: as this merge moves almost all files, it is recommended to make a backup of your working copy before updating your working copy.