Update bitcoin-core GitHub links

Author: MarcoFalke

README.md

@@ -1,7 +1,7 @@
 libsecp256k1
 ============
 
-[![Build Status](https://travis-ci.org/bitcoin/secp256k1.svg?branch=master)](https://travis-ci.org/bitcoin/secp256k1)
+[![Build Status](https://travis-ci.org/bitcoin-core/secp256k1.svg?branch=master)](https://travis-ci.org/bitcoin-core/secp256k1)
 
 Optimized C library for EC operations on curve secp256k1.
 

libsecp256k1.pc.in

@@ -5,7 +5,7 @@ includedir=@includedir@
 
 Name: libsecp256k1
 Description: Optimized C library for EC operations on curve secp256k1
-URL: https://github.com/bitcoin/secp256k1
+URL: https://github.com/bitcoin-core/secp256k1
 Version: @PACKAGE_VERSION@
 Cflags: -I${includedir}
 Libs.private: @SECP_LIBS@

src/tests.c

@@ -1951,8 +1951,8 @@ void test_add_neg_y_diff_x(void) {
      * of the sum to be wrong (since infinity has no xy coordinates).
      * HOWEVER, if the x-coordinates are different, infinity is the
      * wrong answer, and such degeneracies are exposed. This is the
-     * root of https://github.com/bitcoin/secp256k1/issues/257 which
-     * this test is a regression test for.
+     * root of https://github.com/bitcoin-core/secp256k1/issues/257
+     * which this test is a regression test for.
      *
      * These points were generated in sage as
      * # secp256k1 params