Dependency increase in trunk: aqbanking >= 1.6.0?

[Christian Stimming]

Hi devs,

for all those out there who'd like to use the online banking features, be it 
through OFX DirectConnect or HBCI, I'd like to increase the dependency on 
aqbanking. Both online banking families really only work correctly with 
aqbanking >= 1.6.0 (released 2005-09-22) anyway.

I'd like to increase the dependency in trunk to require aqbanking >= 1.6.0. 
Allowing older aqbanking versions is needed probably only for those people 
who would like to compile with --enable-aqbanking but don't actually use the 
online banking features themselves, because if they did, they would be using 
a newer aqbankign anyway. In fact, the reports of successful OFX Direct 
Connect even required aqbanking >= 2.0.0 (released 2006-04-03)... 

So I'd like to increase this *optional* dependency for the very same reason 
that it is optional. If any older distro doesn't have that, well, fine with 
us, simply don't use --enable-aqbanking. If anyone intends to use the online 
banking features, they would update anyway... and yes, my only reason is that 
I'm too lazy to test for that very old aqbanking code. The API has seen quite 
a bunch of additions at 1.6.0. It is surely possible to keep the code 
backward-compatible, but I don't want to spend that extra (substantial) 
effort because the people with older aqbanking don't use that part of gnucash 
anyway.

Objections, anyone from the dev side? Again, this only concerns trunk and not 
branch-2.0.

Christian