New 9.x branch: developers, please test

[jamespetts]

I am preparing for the forthcoming release of Simutrans-Experimental 9.0. In preparation for that release, I have pushed a 9.x branch to my Github repository. It incorporates all of the latest changes to Standard, a considerable number of bug fixes and a few small new features and enhancements (see the Git commit logs for details). I should be grateful if all those with the ability to compile the code could have a go at testing this before I release a binary version to chase out as many bugs as possible: I have found a few in the last couple of weeks. I should be grateful if any bug reports were posted in their own specific topics: one topic per bug. Thank you!

[inkelyad]

Climate dialog fix.
button_t::square replaced with button_t::square_state
for 'Hilly landscape' and 'Cities ignore height'

[jamespetts]

After much delay during which I have been preoccupied with other things, I have updated this branch with one or two fixes and all the latest changes from Standard. Further testing would be much appreciated.

Inkelyad - what is the advantage of the attached patch (apologies for not reverting to you sooner on it) and is it possible to put it on Github for ease?

[inkelyad]

It was impossible to toggle 'Hilly landscape' button. You already fixed this.