Updates to fix latex build of docs. (#539)

The LaTeX builder did not work with SVGs so I converted them to pngs. I
also fixed some incorrect LaTeX math and dealt with a few stray
backslashes that were failing the build.

With these changes, the Sphinx LaTeX builder works properly and xelatex
builds a full pdf appropriately.

It's not a perfect PDF in that the introductory sections are added as
top level chapters to the end of the document, but other than that it is
pretty good.

README.rst

@@ -1,4 +1,9 @@
-|Build Status| |Code Coverage|
+
+.. The LaTeX builder doesn't support SVGs, and these badges are SVGs
+
+.. only:: html
+
+  |Build Status| |Code Coverage|
 
 The Advanced Reactor Modeling Interface (ARMI\ :sup:`®`) is an open-source tool that
 streamlines your nuclear reactor design/analysis needs by providing a

armi/reactor/blocks.py

@@ -1297,9 +1297,8 @@ def getMfp(self, gamma=False):
 
         .. math::
 
-
-            <\Sigma> = \frac{\sum_E(\phi_e*\Sigma_e*dE)}{\sum_E (\phi_e*dE)}  =
-            \sum_E(\phi_e*N*\sum_{\text{type}}(\sigma_e)  dE}{\sum_E (\phi_e*dE))}
+            <\Sigma> = \frac{\sum_E(\phi_e \Sigma_e dE)}{\sum_E (\phi_e dE)}  =
+            \frac{\sum_E(\phi_e N \sum_{\text{type}}(\sigma_e)  dE}{\sum_E (\phi_e dE))}
 
         Block macro is the sum of macros of all nuclides.
 

armi/reactor/grids.py

@@ -1132,14 +1132,14 @@ class CartesianGrid(Grid):
 
     These concepts are illustrated in the example drawings below.
 
-    .. figure:: ../.static/through-center.svg
+    .. figure:: ../.static/through-center.png
         :width: 400px
         :align: center
 
         Grid example where the axes pass through the "center assembly" (odd-by-odd).
         Note that ring 1 only has one location in it.
 
-    .. figure:: ../.static/not-through-center.svg
+    .. figure:: ../.static/not-through-center.png
         :width: 400px
         :align: center
 

doc/user/accessingEntryPoints.rst

@@ -8,14 +8,13 @@ Reports Entry Point
 There are two ways to access the reports entry point in ARMI.
 
 The first way is through a yaml settings file.
-Here, the call is as follows
+Here, the call is as follows::
 
-``(venv) C:\Users\username\codes> tparmi report anl-afci-177.yaml``
+    (venv) C:\Users\username\codes> tparmi report anl-afci-177.yaml
 
-It is also possible to call this on an h5 file,
+It is also possible to call this on an h5 file::
 
-
-``(venv) C:\Users\username\codes> tparmi report -h5db refTestBase.h5``
+    (venv) C:\Users\username\codes> tparmi report -h5db refTestBase.h5
 
 .. note:: When working with a h5 file, -h5db must be included