Revisit elements that failed to parse because of undefined types

This is to solve cases when type references precede their definition
within a single .gir file.
Handle indirection reflected in c:type when mapping types
Fix name of varargs argument

The name of at least one varargs argument is given in the girs as
"...". This is not a valid name for a Java method argument, so
hardwire it to "varargs" instead.
Add pretty wrappers for methods taking or returning pointers
Add missing isInstance flag to ParameterDescriptor
Pass a pointer to this to instance parameters in pretty wrappers
Create namespace-wide class for non-class functions

Functions/methods not declared within a <class> or <record> in
a gir file now get their Java side in a namespace-wide functions
class in the root package of the generated code. For example,
such functions in the namespace Gst are currently added to
generated.Gst.