Move secp256k1 lib from sipa's (long expired) repo to the bitcoin one

.travis.yml

@@ -1,7 +1,7 @@
 language: rust
 
 install:
-  - git clone https://github.com/sipa/secp256k1.git
+  - git clone https://github.com/bitcoin/secp256k1.git
   - cd secp256k1
   - ./autogen.sh && ./configure && make && sudo make install
   - sudo ldconfig /usr/local/lib

Cargo.toml

@@ -1,8 +1,16 @@
 
 [package]
 name = "bitcoin"
-version = "0.0.1"
+version = "0.1.0"
 authors = ["Andrew Poelstra <apoelstra@wpsoftware.net>"]
+license = "CC0-1.0"
+homepage = "https://github.com/apoelstra/rust-bitcoin/"
+repository = "https://github.com/apoelstra/rust-bitcoin/"
+documentation = "https://www.wpsoftware.net/rustdoc/bitcoin/"
+description = "General purpose library for using and interoperating with Bitcoin and other cryptocurrencies."
+keywords = [ "crypto", "bitcoin" ]
+readme = "README.md"
+
 
 [lib]
 name = "bitcoin"