update installation instructions

content/install.rst

@@ -222,7 +222,7 @@ dependencies so that you can use the `IPython notebook <http://ipython.org/noteb
 
 
 ``conda``
----------
+=========
 ``conda`` is the package manager for the Anaconda Python distribution.
 
 Kwant currently has ``conda`` packages for GNU/Linux and Mac OS X platforms.
@@ -291,7 +291,7 @@ for these libraries; you will need to install the `-dev` or `-devel` versions
 of the packages.
 
 As an example, on a Debian or Ubuntu system, the following
-command will install the non-Python prerequisites of Kwant::
+command will install the non-Python dependencies of Kwant::
 
     sudo apt-get install build-essential gfortran libopenblas-dev liblapack-dev libmumps-scotch-dev
 
@@ -314,7 +314,7 @@ installing kwant::
 
 
 Building from source
---------------------
+====================
 If no packages are available for the system you use, or if you would like to
 build Kwant from source for another reason (expert users may want to customize
 Kwant to use certain optimized versions of libraries), please consult the