Small fixes.

doc/install.txt

@@ -113,7 +113,7 @@ All tests should pass. If some test fails on your machine, you are
 encouraged to tell us what went wrong on the :ref:`theano-users` mailing
 list.
 
-To update your library to the latest revision, change directory (`cd`)
+To update your library to the latest revision, change directory (``cd``)
 to your `Theano` folder and execute the following command:
 
 .. code-block:: bash
@@ -135,11 +135,11 @@ automatic code generation, but that way is much, much slower.
 - `THEANO_BLAS_LDFLAGS`:
     A space-separated list of options (flags) that will be passed to the
     compiler. It should include library names to link against for BLAS
-    functions. Default: `-lblas`.
+    functions. Default: ``-lblas``.
 
 - `THEANO_COMPILEDIR`:
     A directory with read/write access permissions where theano will store
-    autogenerated code and C modules. Default: `$HOME/.theano`. If this
+    autogenerated code and C modules. Default: ``$HOME/.theano``. If this
     directory does not exist or does not have the correct permissions,
     theano will try to create it with the correct permissions. If that fails,
     an exception will be raised and no C code will be compiled.
@@ -149,9 +149,11 @@ automatic code generation, but that way is much, much slower.
     graphs. This can be one of the strings defined in
     :api:`theano.compile.mode`.
     Possible values so far are:
+
     - FAST_COMPILE,
     - FAST_RUN and
     - DEBUG_MODE.
+
     Omitting this variable defaults the mode to FAST_RUN.
 
 - `THEANO_UNITTEST_SEED`: