IGV download path

IGV download path has changed so software_task file needs to be changed to:

```
# IGV is licensed, please register
# you should register here https://www.broadinstitute.org/software/igv/?q=registration
- name: Downloading IGV {{version}}
get_url: url="http://data.broadinstitute.org/igv/projects/downloads/{{sub}}/IGV_{{version}}.zip" dest="{{source_dir}}/IGV_{{version}}.zip"

- name: Uncompressing IGV
unarchive:
src="{{source_dir}}/IGV_{{version}}.zip"
dest="{{software_dir}}"
copy=no
creates="{{software_dir}}/IGV_{{version}}/igv.sh"

- name: Installing IGV
file: src="{{software_dir}}/IGV_{{version}}/igv.sh" dest=/usr/local/bin/igv.sh state=link
```
And the main_software.yaml needs the addition of a new variable called sub.

NOTE - igvtools is no longer in this download folder so this software_task is also broken but I don't need it so not searched for it.

Start by reading the software_task file and main_software.yaml, focusing on the IGV download configuration and its version variables. Update the IGV path and add the requested sub variable, then verify that the installation steps use the current download location; igvtools is noted as broken but is outside the requested need.

Written by the indexing model from the issue text.