readme: use 'python3 -m pip install' to install

README.rst

@@ -41,7 +41,7 @@ directory. To run Electrum from its root directory, just do::
 You can also install Electrum on your system, by running this command::
 
     sudo apt-get install python3-setuptools
-    pip3 install .[fast]
+    python3 -m pip install .[fast]
 
 This will download and install the Python dependencies used by
 Electrum, instead of using the 'packages' directory.
@@ -64,7 +64,7 @@ Check out the code from GitHub::
 
 Run install (this should install dependencies)::
 
-    pip3 install .[fast]
+    python3 -m pip install .[fast]
 
 Render the SVG icons to PNGs (optional)::
 

electrum-env

@@ -17,7 +17,7 @@ if [ -e ./env/bin/activate ]; then
 else
     virtualenv env -p `which python3`
     source ./env/bin/activate
-    python3 setup.py install
+    python3 -m pip install .[fast]
 fi
 
 export PYTHONPATH="/usr/local/lib/python${PYTHON_VER}/site-packages:$PYTHONPATH"