Slide viewer not working when hosting on remote machine

[maor121]

Reproduce:

1. Host HistomicsML on a machine, and try to access it from another machine.
   example: http://ip-not-localhost/HistomicsML
2. Open new session
3. Slideviewer not working. Error is : "...HTTP 0 attempting to load TileSource"

Workaround:
On chrome, open network debug, start new session.
Apparrantly, behind the scenes the browser access:
http://localhost/fcgi-bin/iipsrv.fcgi?DeepZoom=/localdata/pyramids/GBM/TCGA-02-0010-01Z-00-DX4.svs.dzi.tif_files/9/0_1.jpg

As a temporary workaround:

1. On HistomicsML website Reset Session (so no leftovers will be left).
2. On the docker machine, run:
   docker exec -t -i histomicsml_hmlweb_1 bash
   service al_server stop
   cd d /var/www/html/HistomicsML/php
   vi hostspecs.php
3. change this line:
   $IIPServer = "http://localhost/fcgi-bin/iipsrv.fcgi?";
   to
   $IIPServer = "http://ip-not-localhost/fcgi-bin/iipsrv.fcgi?";
   where ip-not-localhost is the external ip of the docker machine, this ip is forwarded to the client browser.
4. service al_server start

Note: The hostspecs.php file also have another line with 'localhost' inside, DO NOT CHANGE IT.
When I did, I got connection refused when trying to start a session. Maybe it's bad luck. I don't know.