add manual install instructions

##### Running the script

git clone

Adding the script to the PATH is not absolutely neccessary, it can

be called as follows from the directory that it is downloaded in.

```

cd $HOME/Downloads

git clone https://github.com/TomKellyGenetics/universc.git

cd universc

bash launch_universc.sh

```

##### Manual configuration

You can manually add the script here to the PATH, for example:

```

PATH=$HOME/Downloads/universc:$PATH

```

This means that the directory where the script is can be found

from the shell.

```

echo $PATH

cd ~

launch_universc.sh

```

Add the following line to the `~/.bashrc` file and use `source ~/.bashrc`

to load a new session. This means that you do not need to add the

sript to the PATH in future sessions.

```

export PATH=$HOME/Downloads/universc:$PATH 

```

####

```