The SAIP specification is very weird in a way that it treats the DF and
EF descriptions as some kind of flat structure without describing the
hierarchy. So when creating a DF, sometimes it should be created below
the current DF, and sometimes it should be adjacent next to the current
DF.
Let's introduce
* a 'ppath' property of FileTemplate to indicate if a file is anything
but a direct sibling of the 'base DF' of the PE
* an 'extends' property of ProfileTemplate to indicate that a given
template does not have its own 'base DF', but that its contents merely
extends that of another ProfileTemplate
* a 'parent' property of ProfileTemplate to indicate a parent
ProfileTemplate below whose 'base DF' our files should be placed.
Change-Id: Ieab4835cd21008b289713784c0eb7170af2ccfb9
89dff98fb6