Changed UnitKit to use a simple autorelease pool rather @autoreleasepool (for GCC compatibility and may be not well tested @autoreleasepool without ARC on GNUstep)

git-svn-id: http://svn.gna.org/svn/etoile/trunk/Etoile/Frameworks/UnitKit@10501 7b3f36aa-e6db-49c1-8b4c-66eac1997e64