Read the docs config file, setup.py doc requirements

.readthedocs.yml

@@ -0,0 +1,13 @@
+requirements_file: requirements.txt
+
+build:
+    image: latest
+
+python:
+  version: 3.6
+  pip_install: true
+  extra_requirements: [docs]
+
+formats:
+  - epub
+  - pdf

setup.py

@@ -31,7 +31,7 @@ def read(fname):
     setup_requires=["pytest-runner"],
     tests_require=["pytest", "pytest-cov"],
     install_requires=["WrightTools>=3.0", "numpy", "scipy", "matplotlib", "tidy_headers"],
-    extras_require={"dev": ["black", "pre-commit"]},
+    extras_require={"dev": ["black", "pre-commit"], "docs": ["sphinx-gallery>0.3.0", "sphinx", "sphinx-rtd-theme"]},
     version=version,
     description="Tools for tuning optical parametric amplifiers and multidimensional spectrometers.",
     long_description=read("README.rst"),