Bug 921890: Add key extraction and signature verification to insanity::pkix, r=keeler, r=cviecco

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extra : rebase_source : c94380aedc563b3eecddb9bcac60b532f5799eee
extra : source : e33ed267eeee330807dff6c6347e11c0a4e86809
Bug 921887: Add minimal DER decoder to insanity::pkix, r=keeler

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extra : rebase_source : 12becc63c3f1d4f04f0164d236b6759e9f4e81cc
extra : source : 6db5ba057f8d557eaf238d35d539e4c3dc08be1a
Bug 921889: Add minimal std::bind/ref/cref polyfill to insanity::pkix, r=keeler

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extra : rebase_source : fe8677986461e9d81e471df91360f98b3dd0c97f
extra : source : 6f777ffc1bbc4f3575a0f2c8c1dc63b0fa4b02b0
Bug 921891, Part 1: Add insanity::pkix::Result and insanity::pkix::TrustDomain, r=keeler, r=cviecco

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extra : rebase_source : 2157dbe076e0f50d7c618964804fd17d7e735904
extra : source : 682de9276170560ac62d5bc5ffbe5b707060321b
Bug 921888: Fix nullptr workaround to work with clang, r=cviecco

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extra : rebase_source : 39e8badba1865a695bca49b2fbd4b266c804f361
extra : source : 259e4540e192da66a2ec5cdd26dfc43d506c51c6