NF+BK: require that gifti surface files have the .surf.gii extension rather than .gii only to conform better to the gifti standard
RF: split gifti writing into multiple stages
RF: moved some general surface stuff to surf from surf_fs_asc
NF+BK: prep-afni-surf now writes GIFTI files by default (change with "-f ascii"). TODO/XXX still need to consider how AFNI/SUMA treat LPI/RAI orientation overlay issues as reported on "http://afni.nimh.nih.gov/afni/community/board/read.php?1,141432,141432"
PL: whitespace fixes
NF: CompoundLearner and subclasses ChainLearner and CombinedLearner
ENH: back to ascci surfaces as the default as long as gifti issues with AFNI are not resolved
RF: simplify gifti surface I/O