Throw a warning if a invalid (not present) AI is specified in a map.
Replace the last occurences of jubot with qbot.
Exclude the common siege templates from the Units Demo map.
Fix an error with flying units.
Replace CFG_GET_SYS_VAL with CFG_GET_USER_VAL and rename it to
CFG_GET_VAL to reflect its behaviour better.
Fix linker error with clang 3.2. Refs 1588.
Remove some useless includes.
This was SVN commit r13031.