Updated README.md with OSX install fixes

README.md

@@ -11,7 +11,7 @@ It's easiest to install with `pip`:
 $ pip install --user abp==0.4.27
 ```
 
-Or clone and install in `develop` mode:
+Or install from source: clone and install in `develop` mode:
 
 ```shell
 $ git clone https://github.com/peteshadbolt/abp.git
@@ -19,4 +19,13 @@ $ cd abp
 $ python setup.py develop --user
 $ python setup.py develop --user --prefix=  # Might be required on OSX
 ```
+If installed from source, check that abp is running your local Python install by ensuring that the first line of `abp/bin/abpserver` matches your local python install (which can be found using `which python`). If not, you will need to change it to your local python path.
+
+Some OSX users may find they need additional modifications to their install. their path to execute `abpserver` from the command line. To add `abpserver` to your path, you must find where it is installed, e.g. using the search:
+
+```shell
+$ find / -iname "abpserver"
+```
+A path to a Python library, such as `/Users/username/Library/Python/2.7/bin/abpserver`, should appear (if installed from source, this is not `path/to/repo/abp/bin/abpserver`). To add this to your path permanently, open `~/.bash_profile`, add the path, e.g. `export PATH="$HOME/Library/Python/2.7/bin:$PATH"` and restart your shell. If this has worked, typing `which abpserver` will display the desired path.
+