Can use custom function to process function name

Let the user to define a custom function to process the, getter and
setter, function name. If the custom function doesn't exist, it will
fall back to the normal flow.

ftplugin/php_getset.vim

@@ -501,7 +501,12 @@ if !exists("*s:ProcessVariable")
   function s:ProcessVariable(variable)
     let s:indent    = substitute(a:variable, s:variable, '\1', '')
     let s:varname   = substitute(a:variable, s:variable, '\4', '')
-    let s:funcname  = toupper(s:varname[0]) . strpart(s:varname, 1)
+
+    if exists("*PhpGetsetProcessFuncname")
+        let s:funcname = PhpGetsetProcessFuncname(s:varname)
+    else
+        let s:funcname  = toupper(s:varname[0]) . strpart(s:varname, 1)
+    endif
 
     " If any getter or setter already exists, then just return as there
     " is nothing to be done.  The assumption is that the user already