Apache FOP Layout update

Layout update
by
AD
:

PropertyCache phase 2:
• improvement of the PropertyCache itself should now guarantee acceptable
performance of the static caches in multi-session environments, which is
a possible problem with synchronizedMap.
• changed CommonFont to use the cache:
added CachedCommonFont to contain the properties that are always cacheable
CommonFont itself is only cached if the remaining properties are absolutes.
• changed CommonHyphenation, KeepProperty, ColorProperty and FontFamilyProperty to use the cache.