Merge pull request #4100

a0495bb Add <Hasher>::OUTPUT_SIZE (Pieter Wuille)
4791b99 crypto: create a separate lib for crypto functions (Cory Fields)
f2647cc crypto: explicitly check for byte read/write functions (Cory Fields)
5437248 build: move bitcoin-config.h to its own directory (Cory Fields)
3820e01 Extend and move all crypto tests to crypto_tests.cpp (Pieter Wuille)
7ecd973 Move {Read,Write}{LE,BE}{32,64} to common.h and use builtins if possible (Pieter Wuille)
a5bc9c0 Add built-in RIPEMD-160 implementation (Pieter Wuille)
13b5dfe Move crypto implementations to src/crypto/ (Pieter Wuille)
1cc344c Add built-in SHA-1 implementation. (Pieter Wuille)
85aab2a Switch miner.cpp to use sha2 instead of OpenSSL. (Pieter Wuille)
cf0c47b Remove getwork() RPC call (Pieter Wuille)
7b4737c Switch script.cpp and hash.cpp to use sha2.cpp instead of OpenSSL. (Pieter Wuille)
977cdad Add a built-in SHA256/SHA512 implementation. (Pieter Wuille)