* update build instructions

Readme.md

@@ -16,14 +16,16 @@ Once you have the above requirements, you will create a virtual environment from
 In principle, it doesn't matter where your Python installation comes from except that it cannot come from Anaconda.
 I do not know exactly why an Anaconda installation does not work except that it has something to do with hardlinks.
 
-I recommend using [Homebrew](http://brew.sh/) to install Python, along with pyenv and pyenv-virtualenv (if you plan to use these for virtual environment management).
+I recommend using [Homebrew](http://brew.sh/) to install pyenv and pyenv-virtualenv (if you plan to use these for virtual environment management).
+If you plan to use pyenv, you don't even need to install Python from Homebrew, since pyenv will install whatever python version you request.
+If you don't plan to use pyenv, then you will need to install Python from Homebrew or elsewhere.
 
 After installing Homebrew, run:
 ```
-$ brew install python3, pyenv, pyenv-virtualenv
+$ brew install pyenv, pyenv-virtualenv
 ```
 
-If you use pyenv must enable frameworks in your Python installation, as follows.
+If you use pyenv you must enable frameworks in your Python installation, as follows.
 If you are using venv, you can ignore this.
 ```
 $ PYTHON_CONFIGURE_OPTS='--enable-framework'
@@ -40,18 +42,20 @@ If you are using pyenv with pyenv-virtualenv, it will look like this:
 ```
 $ pyenv virtualenv <python version> env-spy-dev
 $ pyenv local env-spy-dev
-(env-spy-dev) $ pip install --upgrade pip
-(env-spy-dev) $ pip install -r requirements.txt
+(env-spy-dev) $ pip install -r req-base.txt -r req-build.txt -r req-user.txt
 ```
-
 If you are using venv, it will look like this:
 ```
 $ python -m venv --clear --copies env-spy-dev
 $ source env-spy-dev/bin/activate
-(env-spy-dev) $ pip install --upgrade pip
-(env-spy-dev) $ pip install -r requirements.txt
+(env-spy-dev) $ pip install -r req-base.txt -r req-build.txt -r req-user.txt
 ```
 
+`req-base.txt` contains the minimum required packages for Spyder to run.
+`req-build.txt` contains only those packages required to build the stand-alone application.
+`req-user.txt` contains optional packages to include, if desired, for use in iPython consoles launched from "Same as Spyder" environments.
+If you use external environments, such as conda, for your iPython consoles, you don't need these.
+
 ### Create the Standalone Application
 
 For the build to work properly, your local clones of both spyder and spyder-kernels must be at the same directory level as your local clone of this repository.
@@ -63,3 +67,9 @@ To create the standalone application and package it in a dmg disk image run:
 After a whole lot of screen dump, and if everything went well, you should now have two files in the `dist` folder of this repository:
 * Spyder.app
 * Spyder-\<Spyder version\> Py-\<Python version\>.dmg
+
+The following commandline optional arguments are available:
+* `py2app`: this causes the bundled app to be produced. Omitting this argument will run `setup.py` without building the app.
+* `-A`: This causes py2app to build the application in "alias" mode; basically a quicker way to build the app for debugging, but is not very reliable.
+* `--lite`: This will cause py2app to exclude the optional user packages from the application bundle (approximately 250MB).
+* `--no-dmg`: This will prevent the dmg disk-image from being created