Log Message:
Update xephem to 3.7.7 with OK from gdt@.

Changes from 3.7.6 to 3.7.7
Released August 9, 2015

    Bugs fixed:

        Improved earth satellite range rate
        Fixed some typos in help file
        Updated magnetic declination model for 2015-2020
        Update Makefile for OS X.10 Yosemite to look for X11 in /opt/X11
        Magnetic declination tooltip was reversed
        Update Minor Planet Center donwloading script, mpcorb2edb.pl
        INDI was not sending all Switches as required by specification.
        Change astorb2edbl.pl to use curl and try both with and without EPSV.

    New features:

        Include new simpleINDI demo program.
        Add support for UCAC4

Changes from 3.7.5 to 3.7.6
Released January 20, 2013

    New features:

        Show transit azimuth
        Plots now show coordinates under cursor.
        Improved Earth night lights file, nearth.gif.
        Update Jupiter Great Red Spot default longitude.
        Show satellite element age in Index.
        Add Curiosity landing coordinates to mars_db
        Separate Sky View horizon clipping option
        SOHO is back
        New daytime earth image with improved geography shading
        SkyView -> Favorites offers same controls as map right-click
        Telescope GoTo honors horizon map

    Bugs fixed:

        Improve Earth sunline in cyl graphic projection near equinox.
        Improve error handling downloading asteroid data.
        Improve accuracy of Earth satellite transits.
        Significantly improve speed of Earth satellite rise and set predictions.
        Significantly improve accuracy of Earth satellite transit predictions.
        Eliminate Earth satellite Objects table values flashing.
        Improve accuracy of Earth satellite ground footprint.
        Saving Favorites after downloading new elements now saves new values.
        Improved earth satellite height and solver stability.
        Improve INDI menu interactions for type ISwitchVectorProperty
        Sky view horizon clipping incorrectly in rare cases.
        Better isolation of applicable Sky View options in individual planet \ 
rendering.
        In Moon view: subearth, subsolar and anti-subsolar options moved from \ 
Grid to {Pen}Umbra.
        Show sun in moonview during solar eclipse
        Better handling of proxies and large files in web downloads
        Favorites menu updates when db that is also a favorite changes.
        Fixed crash if Earth view showing Favorite that is updated from file or \ 
download