client-gli needs to have Download panel

[ak19]

Need installer for client-gli

[ak19]

Changed configRemote.xml by setting the Workflow section's Download Panel element to true. Need to test this still when I test the remote greenstone server.

[ak19]

Updated DownloadPane.java and gliserver.pl so that the DownloadPanel now appears in client-gli.

[ak19]

See #520

How it should work:

1. gli

[ak19]

1. gli should contain gs2build
2. client-gli.bat/client-gli.sh should start with the flag -gsdlhome set to gs2build's path (this indicates where the bin and perl script folders and everything are)
3. In GLI code, need to check in GSDLRemote case if -gsdlhome is set. If it isn't, then the download pane should not become enabled. If -gsdlhome is set in GSDLRemote case, then building should be done locally as well.

[ak19]

Did it the above way, but then we had a discussion and it was redone: Client-gli looks for any local GS installation and uses the GSDLHOME set there to find the gs2building directory for the scrips and executables--like wget--needed for downloading. If GSDLHOME exists then the Download panel becomes available. If it doesn't, then client-gli launches as before: no download panel.

Done and checked for both Linux and Windows.

Took the opportunity to tidy up the gli start-up scripts. Now some reused code is moved into separate scripts and gets called from both client-gli and gli batch scripts. Repeated for Linux for the purposes of symmetry.