Removed jwt directory as it has duplicate code in src. (#15)

The src directory was made of original files plus some files pulled from
other gir repos. The workflow was supposed to be to edit the original
files in jwt/ directory, call jwt/compile.sh, then copy the output to
src. The new workflow is to edit files in src except for the src/crypto
folder because files in that folder are pulled from external repos.

CONTRIBUTING.md

@@ -3,6 +3,14 @@
 We'd love to accept your patches and contributions to this project. There are
 just a few small guidelines you need to follow.
 
+## Editing files in src/crypto
+
+The files in src/crypto are pulled from external git repositories. They are not
+submoduled so that this repo can be exported as an Arduino library. If you want
+to modify prng.*, modify it directly in this repo. If you want to modify other
+file either modify them using pull_crypto.sh, or modify them in the repos they
+are pulled from.
+
 ## Contributor License Agreement
 
 Contributions to this project must be accompanied by a Contributor License

pull_crypto.sh

@@ -0,0 +1,62 @@
+#!/bin/bash
+#******************************************************************************
+# Copyright 2018 Google
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#****************************************************************************
+
+
+# This script pulls the latest source files from github into the jwt/crypto
+# folder. Run it from it's directory to get the latest files.
+
+# Make temp directory, cd into it.
+mkdir tmp
+cd tmp
+
+# Clone ecc libraries.
+git clone https://github.com/cirvladimir/ecc-light-certificate.git
+git clone https://github.com/CSSHL/ESP8266-Arduino-cryptolibs.git
+
+# cd out of tmp.
+cd ..
+
+# Copy sources into jwt folder.
+cp tmp/ESP8266-Arduino-cryptolibs/sha256/sha256.cpp src/crypto/sha256.cpp
+cp tmp/ESP8266-Arduino-cryptolibs/sha256/sha256.h src/crypto/sha256.h
+cp tmp/ecc-light-certificate/ecc/curve-params/secp256r1.c src/crypto/secp256r1.cpp
+cp tmp/ecc-light-certificate/ecc/ecc.c src/crypto/ecc.cpp
+cp tmp/ecc-light-certificate/ecc/ecc.h src/crypto/ecc.h
+cp tmp/ecc-light-certificate/ecc/ecdsa.c src/crypto/ecdsa.cpp
+cp tmp/ecc-light-certificate/ecc/ecdsa.h src/crypto/ecdsa.h
+cp tmp/ecc-light-certificate/ecc/nn.c src/crypto/nn.cpp
+cp tmp/ecc-light-certificate/ecc/nn.h src/crypto/nn.h
+
+# Remove unnecessary sha library.
+sed -i '/#include "sha2.h"/d' src/crypto/ecdsa.h
+# Add some defines since we're not using make.
+sed -i '1i#define SHA256_DIGEST_LENGTH 32' src/crypto/ecdsa.h
+sed -i '1i#define THIRTYTWO_BIT_PROCESSOR' src/crypto/nn.h
+sed -i '1i#define SECP256R1' src/crypto/nn.h
+
+# Change string.h to String.h
+for f in src/crypto/ecdsa.cpp src/crypto/nn.cpp src/crypto/secp256r1.cpp src/crypto/sha256.cpp
+do
+  sed -i 's/#include <string.h>/#include <String.h>/' $f
+done
+
+# Add a do not edit comment.
+for f in src/crypto/sha256.cpp src/crypto/sha256.h src/crypto/secp256r1.cpp src/crypto/ecc.cpp src/crypto/ecc.h src/crypto/ecdsa.cpp src/crypto/ecdsa.h src/crypto/nn.cpp src/crypto/nn.h
+do
+  sed -i '1i// AUTOGENERATED, DO NOT EDIT. See CONTRIBUTING.md for instructions.' $f
+done
+
+rm -rf tmp

src/crypto/ecc.cpp

@@ -1,3 +1,4 @@
+// AUTOGENERATED, DO NOT EDIT. See CONTRIBUTING.md for instructions.
 /**
  * \addtogroup ecc
  *

src/crypto/ecc.h

@@ -1,3 +1,4 @@
+// AUTOGENERATED, DO NOT EDIT. See CONTRIBUTING.md for instructions.
 /**
  * \defgroup ecc Elliptic Curve Point Arithmetic
  *

src/crypto/ecdsa.cpp

@@ -1,3 +1,4 @@
+// AUTOGENERATED, DO NOT EDIT. See CONTRIBUTING.md for instructions.
 /**
  * \addtogroup ecdsa
  *