Stripped down doc requirements

docs/requirements.txt

@@ -1,34 +1 @@
-openflexure-microscope==1.0.0b0
-
-alabaster==0.7.12
-Babel==2.6.0
-certifi==2018.11.29
-chardet==3.0.4
-Click==7.0
-docutils==0.14
-Flask==1.0.2
-future==0.17.1
-idna==2.8
-imagesize==1.1.0
-itsdangerous==1.1.0
-Jinja2==2.10
-MarkupSafe==1.1.0
-numpy==1.15.4
-openflexure-stage==0.2.1
-packaging==18.0
-picamera==1.13
-Pillow==5.4.1
-Pygments==2.3.1
-pyparsing==2.3.0
-pyserial==3.4
-pytz==2018.9
-PyYAML==3.13
-requests==2.21.0
-RPi.GPIO==0.6.5
-six==1.12.0
-snowballstemmer==1.2.1
-Sphinx==1.8.3
-sphinxcontrib-httpdomain==1.7.0
-sphinxcontrib-websupport==1.1.0
-urllib3==1.24.1
-Werkzeug==0.14.1
+openflexure-microscope==1.0.0b0