Merge pull request #1465 from ttilberg/patch-1

Fixed typo in `build-essential`

Author: ericholscher

docs/custom_installs/local_rtd_vm.rst

@@ -8,7 +8,7 @@ Assumptions and Prerequisites
 * All python dependencies and setup tools are installed ::
 
   $ sudo apt-get install python-setuptools
-  $ sudo apt-get install built-essential
+  $ sudo apt-get install build-essential
   $ sudo apt-get install python-dev
   $ sudo apt-get install libevent-dev
   $ sudo easy_install pip