Don't miscast when the spell can still be aborted (#4281).

This is a significant refactoring. All the spells now return a spret_type and
take a boolean which tells if the spell has actually failed.
Also some code clean up in _do_cast(). All spells have their own function now.

Also fix the following bugs:
* Properly abort fire storm if forced casting on a wall with '!'.
  Also put a message for forced out of range casting (like cloud spells).
* Casting summon elemental on an invisible monster aborted with no cost.
* if a summoning spell aborts because create_monster fails, you don't lose a
  turn. You still get a chance of miscast in this rare case.
* s2s, tukima and branding spells abort properly instead of consuming turn and
MP when player is not wielding appropriate object.
* s2s abort message when wielding a non-snakable.

1 files changed, 4 insertions, 2 deletions

diff --git a/crawl-ref/source/spl-monench.h b/crawl-ref/source/spl-monench.h
index 2a27e36b2d..01fb344e0c 100644
--- a/crawl-ref/source/spl-monench.h
+++ b/crawl-ref/source/spl-monench.h
@@ -1,13 +1,15 @@
 #ifndef SPL_MONENCH_H
 #define SPL_MONENCH_H
 
-void cast_mass_sleep(int pow);
+#include "spl-cast.h"
+
+spret_type cast_mass_sleep(int pow, bool fail);
 void cast_tame_beasts(int pow);
 bool backlight_monsters(coord_def where, int pow, int garbage);
 
 //returns true if it slowed the monster
 bool do_slow_monster(monster* mon, const actor *agent);
 
-bool project_noise();
+spret_type project_noise(bool fail);
 
 #endif