bump version to 13.20 production
remove misleading image about translation process
[fix] don't create a cron which may send a mail each minute ...
typography
clarify documentation around file/web service directories
add mail configuration documentation
updated git info git.xivo.fr to github.com
Merge branch 'master' of ssh://github.com/xivo-pbx/xivo-doc
Merge remote-tracking branch 'origin/bug-4725'
Merge branch 'master' of github.com:xivo-pbx/xivo-doc
typography
update voicemail errors during creation
update information on Snom devices
a user must be unassociated before deleting a voicemail in RESTAPI 1.1
use :menuselection: and :guilabel: presentation mark
correct third point : distinguish the two labels
add configuration and prerequisit information for the snom switchboard
Merge branch '4684_delete_voicemail'

* 4684_delete_voicemail:
  a user must be unassociated before deleting a voicemail in RESTAPI 1.1
Merge branch '4683_voicemail_creation'

Conflicts:
	source/api_sdk/rest_api/1.1/voicemails.rst
tag unimplemented sections in REST API voicemail