Merge pull request #350 from myshkin/restruct

Fix crash when reading a scroll of light.
Replace FEAT_LIGHTING_* by LIGHTING_*
Ensure a predicate for each SQUARE_* flag
Replace sqinfo_has with predicates
Disambiguate square_istrap
Start moving missile and spell animations to map drawing routines
Fixed loop index in find_artifact() (thanks to shadowsun for report in
IRC).
Removed double use of loop index variable in ranged_helper() to prevent
multiple missile hits when monster is at the maximum range of the
missile. Thanks to shadowsun for the bug report.