Replace DANSE links

[Tieqiong]

Currently all danse related links (danse.us) are not working. Replace with working ones, legacy page, or just remove the links.

@sbillinge do we still want this link? (in documentations and the about tab in pdfgui and click the Danse icon).

[sbillinge]

there is a danse legacy page here:
https://www.its.caltech.edu/~matsci/btf/DANSE_web_page.html

We could use this where we want to link to a legacy page, but other places we can delete it. Could you do a global search for this and we can decide?

[Tieqiong]

There are three places in this package that the original danse.us link is mentioned.

• AUTHORS.rst:

DiffPy was initiated as part of the Distributed Data Analysis of Neutron
Scattering Experiments (DANSE) project, funded by the National Science
Foundation under grant DMR-0520547. More information on DANSE can be
found at http://danse.us. Any opinions, findings, and conclusions or
recommendations expressed in this material are those of the author(s)
and do not necessarily reflect the views of the NSF.

• user manual (including the pdf version and html version):

The tutorial directory contains an advanced script
``tui_mno_bond_lengths.py'', which extracts the shortest
Mn-O bond lengths from the same PDFgui project. Please, see
the comments in the script for detailed explanation.

To learn more about the tui module and about the objects
and functions that it returns, please see the API
documentation for diffpy.pdfgui at
@url{http://docs.danse.us/diffraction/diffpy.pdfgui/}.

• danse site button in the about tab in the gui (along with NSF, MSU, and Columbia sites buttons):

def onNsfLogo(self, event):  # wxGlade: DialogAbout.<event_handler>
    launchBrowser("https://www.nsf.gov")
    event.Skip()

def onDanseLogo(self, event):  # wxGlade: DialogAbout.<event_handler>
    launchBrowser("http://danse.us")
    event.Skip()

def onMsuLogo(self, event):  # wxGlade: DialogAbout.<event_handler>
    launchBrowser("https://www.msu.edu")
    event.Skip()

def onColumbiaLogo(self, event):  # wxGlade: DialogAbout.<event_handler>
    launchBrowser("https://www.columbia.edu")
    event.Skip()

as well as the corresponding test function.

@sbillinge So I think we can provide the legacy page for the AUTHOR.rst and gui link, and correct the api link in the manual. How does it sound?