setup.py: Always include develop dependencies on RTD

docs/requirements.txt

@@ -1,3 +0,0 @@
-sphinxcontrib-httpdomain
-sphinxcontrib-napoleon
-sphinx_rtd_theme

requirements-dev.txt

@@ -1,6 +1,12 @@
+# Testing dependencies
 mock>=1.0.1
 nose>=1.3.0
-sphinxcontrib-httpdomain
-sphinx_rtd_theme
-po2json
 ddt
+
+# Documentation dependencies
+sphinxcontrib-httpdomain
+sphinxcontrib-napoleon
+sphinx_rtd_theme
+
+# Translation dependencies
+po2json

setup.py

@@ -250,6 +250,10 @@ def get_cmdclass():
 	return cmdclass
 
 
+def requirements(filename):
+	return filter(lambda line: line and not line.startswith("#"), map(lambda line: line.strip(), open(filename).read().split("\n")))
+
+
 def params():
 	name = "OctoPrint"
 	version = versioneer.get_version()
@@ -287,11 +291,17 @@ def params():
 
 	include_package_data = True
 	zip_safe = False
-	install_requires = open("requirements.txt").read().split("\n")
+	install_requires = requirements("requirements.txt")
 	extras_require = dict(
-		develop=open("requirements-dev.txt").read().split("\n")
+		develop=requirements("requirements-dev.txt")
 	)
 
+	if os.environ.get('READTHEDOCS', None) == 'True':
+		# we can't tell read the docs to please perform a pip install -e .[develop], so we help
+		# it a bit here by explicitely adding the development dependencies, which include our
+		# documentation dependencies
+		install_requires = install_requires + extras_require['develop']
+
 	entry_points = {
 		"console_scripts": [
 			"octoprint = octoprint:main"