restructuring - reorganized code and documentation of 
ft_sourceinterpolate.m, moved most of the bookeeping code from
situation specific to general section at the top.


git-svn-id: svn+ssh://svn.fcdonders.nl/home/svnroot/fieldtrip/trunk@10002 0cf7c7f0-3615-4144-b4e6-68da3bce3cd0
automatically synchronized identical files to revision 10002

git-svn-id: svn+ssh://svn.fcdonders.nl/home/svnroot/fieldtrip/trunk@10003 0cf7c7f0-3615-4144-b4e6-68da3bce3cd0