tools/pyboard.py: Add "touch" filesystem command.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>

docs/reference/mpremote.rst

@@ -131,6 +131,7 @@ The full list of supported commands are:
   - ``rm <src...>`` to remove files on the device
   - ``mkdir <dirs...>`` to create directories on the device
   - ``rmdir <dirs...>`` to remove directories on the device
+  - ``touch <file..>`` to create the files (if they don't already exist)
 
 - mount the local directory on the remote device:
 
@@ -192,8 +193,8 @@ Shortcuts can be defined using the macro system.  Built-in shortcuts are::
 
 - ``c0``, ``c1``, ``c2``, ``c3``: connect to COM?
 
-- ``cat``, ``ls``, ``cp``, ``rm``, ``mkdir``, ``rmdir``, ``df``: filesystem
-  commands
+- ``cat``, ``ls``, ``cp``, ``rm``, ``mkdir``, ``rmdir``, ``touch``, ``df``:
+  filesystem commands
 
 - ``reset``: reset the device
 

docs/reference/pyboard.py.rst

@@ -92,12 +92,13 @@ Filesystem access
 
 Using the ``-f`` flag, the following filesystem operations are supported:
 
-* ``cp src [src...] dest`` Copy files to/from the device.
 * ``cat path`` Print the contents of a file on the device.
+* ``cp src [src...] dest`` Copy files to/from the device.
 * ``ls [path]`` List contents of a directory (defaults to current working directory).
-* ``rm path`` Remove a file.
 * ``mkdir path`` Create a directory.
+* ``rm path`` Remove a file.
 * ``rmdir path`` Remove a directory.
+* ``touch path`` Create a file if it doesn't already exist.
 
 The ``cp`` command uses a ``ssh``-like convention for referring to local and
 remote files. Any path starting with a ``:`` will be interpreted as on the