Makes Travis treat build warnings as errors.

The DM build script now outputs the build log to a file which can then be reviewed from .travis.yml.

.travis.yml

@@ -40,6 +40,7 @@ script:
   - source $HOME/BYOND-${BYOND_MAJOR}.${BYOND_MINOR}/byond/bin/byondsetup
   - cp config/example/* config/
   - scripts/dm.sh -DUNIT_TEST baystation12.dme
+  - grep "0 warnings" build_log.txt
   - DreamDaemon baystation12.dmb -invisible -trusted -core 2>&1 | tee log.txt
   - grep "All Unit Tests Passed" log.txt
   - (! grep "runtime error:" log.txt)

scripts/dm.sh

@@ -44,7 +44,7 @@ if [[ $DM == "" ]]; then
     exit 3
 fi
 
-"$DM" $dmepath.mdme
+"$DM" $dmepath.mdme > build_log.txt
 retval=$?
 
 mv $dmepath.mdme.dmb $dmepath.dmb