First unfinished version of a regression test suite.
Brought back original content of regression_test.py.
Merged trunk.
All tests now run and pass on my system.
Added a missing test.
Let the caller specify the widelands binary to use for regression testing.
Add a --script option to run scripts when loading a game, running a scenario or the editor on the commandline.
Small thinko fix.
Moved save game compatibility tests into the new regression test suite.
Updated docs.
Removed HTML writing as it has not been updated in a very long time. Compile fixes for clang-3.3.
Remove throw() annotations from all methods and functions.
Merged trunk.
Intermediate commit: Added a regression test for expeditions.
Intermediate commit, to be uncommitted.
Intermediate commit.
All tests pass now.
All tests pass.
All done.
Added a regression test suite.

- Added a regression test suite that consists of maps (with scripting) or maps
  or safegames with an external .lua file that and a Python test runner that
  will essentially fire up Widelands and run the Lua scripts, then check the
  output in Python. It is easier than it sounds, just run ./regression_test.py.
- This needed a new --script cmdline option that will run a Lua script directly
  after the game started when used together with --loadgame and --scenario.
- Moved the existing Lua test suite, Lua persistence test suite and
  compatibility safegames into this test suite.
- Added docs to the dev docs how to add a new tests.