speed things up by 33%

by changing Opaque to Qed in various places.  There is more that can
be done by changing Defined to Qed in various places.

Before:

    0.11 sec, 157908992 bytes: Generalities/uuu
    19.81 sec, 1521401856 bytes: Generalities/uu0
    0.32 sec, 584957952 bytes: hlevel1/hProp
    9.47 sec, 1358905344 bytes: hlevel2/hSet
    6.29 sec, 1348255744 bytes: hlevel2/algebra1a
    45.47 sec, 2796535808 bytes: hlevel2/algebra1b
    51.22 sec, 2858303488 bytes: hlevel2/algebra1c
    28.39 sec, 1757970432 bytes: hlevel2/algebra1d
    1.65 sec, 1506738176 bytes: hlevel2/hnat
    6.82 sec, 1493549056 bytes: hlevel2/hz
    16.94 sec, 1633124352 bytes: hlevel2/hq
    1.45 sec, 1475362816 bytes: hlevel2/stnfsets
    2.89 sec, 2352709632 bytes: hlevel2/finitesets
    0.21 sec, 411779072 bytes: Proof_of_Extensionality/funextfun

total 3m 17s

After:

    0.09 sec, 157941760 bytes: Generalities/uuu
    19.67 sec, 1524252672 bytes: Generalities/uu0
    0.33 sec, 585187328 bytes: hlevel1/hProp
    9.56 sec, 1358856192 bytes: hlevel2/hSet
    3.89 sec, 1337360384 bytes: hlevel2/algebra1a
    27.79 sec, 1511014400 bytes: hlevel2/algebra1b
    23.72 sec, 1521795072 bytes: hlevel2/algebra1c
    15.16 sec, 1451753472 bytes: hlevel2/algebra1d
    1.39 sec, 1372192768 bytes: hlevel2/hnat
    6.50 sec, 1358512128 bytes: hlevel2/hz
    16.15 sec, 1422589952 bytes: hlevel2/hq
    1.35 sec, 1337720832 bytes: hlevel2/stnfsets
    2.80 sec, 2166865920 bytes: hlevel2/finitesets
    0.21 sec, 411631616 bytes: Proof_of_Extensionality/funextfun

total 2m 12s