Added basic skeleton for BMAttackSurrender
Add basic unit tests for BMAttackSurrender
Removed 'Surrender' attack type from BMAttack::possible_attack_types(), so it is not listed in the list of possible attack types
Merge remote-tracking branch 'upstream/master' into 174_surrender
Added basic logic for the effect of a BMSurrenderAttack
Merge remote-tracking branch 'upstream/master' into 174_surrender
Merge remote-tracking branch 'origin/174_surrender' into 174_surrender
- Added check to only allow attacks by active player
- Added check that the defender is not the same as the active player
- Added initial unit tests for surrender attack
Fixed type of BMGame->activePlayerIdx
Completed game level surrender unit tests
- Completed interface level surrender unit tests
- Cleared BMGame->attack in BMGame->reset_play_state()
Added unit test for clearing of BMGame->attack in BMGame->reset_game_state()
Merge pull request #377 from blackshadowshade/174_surrender

Added back-end code for surrendering