Fix the requirements.txt file for docs/server, update README.md

docs/README.md

@@ -16,6 +16,14 @@ If you want to generate the HTML version of the long-form documentation on your
 pip install -r requirements.txt
 ```
 
+If you're building the *Server* docs (in `docs/server`) then you must also do:
+```bash
+pip install -e ../../
+```
+
+Note: Don't put `-e ../../` in the `requirements.txt` file. That will work locally
+but not on ReadTheDocs.
+
 You can then generate the HTML documentation _in that subdirectory_ by doing:
 ```bash
 make html

docs/server/requirements.txt

@@ -4,4 +4,3 @@ sphinx-rtd-theme>=0.1.9
 sphinxcontrib-napoleon>=0.4.4
 sphinxcontrib-httpdomain>=1.5.0
 pyyaml>=3.12
-bigchaindb