doc: Add URL to all citations.
doc: Fix publication date of Peterson report.

It was clearly made in 1993, not 2003.
doc: Add Wiggins 1976 bibliography file.
docs: mention DOIs for ObsPy releases together with changelog
docs: adapt seismometer correction examples in tutorial
docs: fix segy API front page (heading levels)
docs: fix obspy.station (had no `__init__.py`)
docs: add some event metadata info to obspy.core front page, plus images
of class structures
doc: Add ChangeLog to table of contents.

Should fix a warning from sphinx about it being orphaned.
doc: Set up deferred JS loading for server-side.
doc: Make images Bootstrap-responsive.
doc: Combine plot:: and include:: directives.

When using the plot directive, the flag :include-source: can be used to
embed the source code above it. This removes the need for a separate
include directive, which could get out of date.
Merge branch 'megies/doc-bootstrap-theme_fixes' into doc-bootstrap-theme
doc: Make images in docstrings responsive too.
doc: Remove duplicate images.

Files in _static are *always* copied to the build directory. But images
that are referenced by some documentation are also copied to _images.
This creates two copies of some images.