Add links to SearchIO documentation pages
Add links to SearchIO tutorial files
Update paths in tutorial after moving example files
Remove docstring reference to CompoundLocation (not merged yet).

Thanks Kai for spotting this.

No need for TravisCI testing, [ci skip]
Bump version ready for Biopython 1.61 release
Today's date for the Biopython 1.61 release
Fixes for epydoc warnings in SearchIO
Fix remaining epydoc warning in SearchIO
Fix epydoc literal sections in SearchIO docstrings
Fix epydoc warning in Bio/__init__.py
Post release version bump
Added the missing DTD file NCBI_Variation.mod.dtd
Nexus: handle & ignore LINK command when parsing (Bug #3408)
Make setup.py warn we're dropping Python 2.5 support
Additional BGZF writing tests from Petra Kubincová
Fix and test BGZF corner case with offset on block boundary
CompoundLocation half done, created as well as sub_features

This modifies the GenBank/EMBL parser and BioSQL loader to create
the CompoundLocation as part of creating the SeqFeature.

NOTE: Need to examine how the location operator (join, order, etc)
should be stored in BioSQL, and what order is used for the location
parts in BioSQL (by the BioPerl loader at least).
Feature location addition (cherry-picked from another branch)
Use CompoundFeatureLocation in GenBank/EMBL output
Label sub_features as obsolete (warnings not very prominent through)