Master account sequence management pvy

the way you split your development is really confusing. i would have expected 
*one branch touching only the sequences in base/ir/ir_sequence.py
*one branch, based on the first one, that modify the module account accordingly, add refund_sequence_id, and so on... 

so i thought here was a branch with everything inside.... but it seems it's not the case, so remove everything not related to account of this PR.

Thanks