Changes for version 2.20

Modules

authenticates DAS requests
authenticates DAS requests by issuing requests to a remote authority
authenticates DAS requests by IP address
configuration parsing and hooks
base class for sources
A ProServer transport module that works off any flat file that Bio::SeqIO supports.
Comma-separated-values transport layer
A DBI transport layer (actually customised for MySQL)
A generic transport layer for deriving others from
Pulls features over command-line SRS/getz transport
A ProServer transport module for wgetz (SRS web access)
adaptor for file-based DAS sources
Builds simple DAS features from a database
A runtime factory for B::D::P::SourceAdaptors
A database-backed implementation of B::D::P::SourceHydra
A database-backed implementation of B::D::P::SourceHydra