Make PhD work with new xml:id's for methods

The new OO skeletons mandate that methods be named as xml:id="classname.methodname". Unfortunately, PhD hasn't been taught to handle these new names properly (Thanks Hannes!) This patch fixes this. We may want to consider factoring the function name <=> munged function name <=> doc filename into its own function as it is something that shows up quite often. -- Edward Z. Yang GnuPG: 0x869C48DA HTML Purifier <http://htmlpurifier.org> Anti-XSS Filter [[ 3FA8 E9A9 7385 B691 A6FC B3CB A933 BE7D 869C 48DA ]]