replace fight_on_without_leader with defeat_condition

[side] now has an attribute defeat_condition which can be "no_leader"(default), "no_units" or "never"
"no_leader" behaves liek it behaved before.
"no_units" behaves like fight_on_without_leader=yes behaved before
"never" is new and causes the side to never get defeated, this usually means the scenariodesigner has to end the scenario with [endlevel]
add "always" defeat_condition
rename remove_from_carryover_on_leaders_loss_

to remove_from_carryover_on_defeat_
add a "radial mode" option to get relative dir. (just for kicks)

Adds a mode for get relative dir which should give radial symmetry,
using vector ops. This might be useful in some application, or to
help debug.
move default relative dir mode to .cpp file, for ease of testing
Update changelog add 'defeat_condition'
don't load null hotkeys

this prevents a possible segfault because otherwise add_hotkey calls hotkey::set_scope_active(new_scope) where new_scope is SCOPE_COUNT.
Merge pull request #165 from gfgtdf/defeat_condition

 replace fight_on_without_leader with defeat_condition
add wml relative dir query tag, and interactive test scenario
Merge branch 'master' of git://github.com/wesnoth/wesnoth
add map location rotate wml interface
fixup radial mode get_relative_dir
get_relative_dir to use radial_symmetry mode, until we fix default

Revert this when we have fixed up the default mode.
Update VC project for b4ea561e37
Fix readme files about unit test scenarios
turn on very verbose logging for wml unit tests on travis

So we can maybe see what's wrong.
fixup map_location unit tests

update the correct test values,
and test the radial mode for characterization as well
disable strict mode on travis, so we can see the error messages
fixup travis unit tests

- travis runs tests not in verbose mode,
  *but* if there is a failure,
  then it runs in very verbose mode, with strict mode off, to get
  errors reported in the travis log.
- run_wml_tests points out that if you don't run in strict mode,
  some tests may not fail as expected, so the count at the end
  may differ
rename values of [side]defeat_condition=

most likely defeat_condition= will re renamed too defeat= too.