Fix possible issues in skin/skin_path config handling (#1490125)

Conflicts:

	program/lib/Roundcube/rcube_plugin.php
Don't trust get_folder(), use $MESSAGE->folder if available
More get_folder() -> $MESSAGE->folder
Fixed typo
Call exif_read_data() only on JPEG images
Fix bug where cancelling switch from HTML to plain text didn't set editor type selector properly (#1490141)
Fix lack of delimiter for recipient addresses in smtp_log (#1490150)
Updated localizations from Transifex
Fix issue where Archive folder wasn't protected in Folder Manager (#1490154)
Merge branch 'release-1.0' of github.com:roundcube/roundcubemail into release-1.0
The following:
  program/steps/mail/compose.inc :: rcmail_store_target_selection()
  program/steps/settings/edit_folder.inc :: rcmail_folder_form()

both try to localise mailbox names.

Push the logic down into the folder_selector() method which can use:

  $this->config->get('show_real_foldernames')

to decide the correct default behaviour.

Clients functions and methods can still override by adding 'realnames'
named parameter to the folder_selector() call. The obvious example is
the Settings -> Preferences -> Special Folders screen.
Update changelog
raoulbhatia: Custom changes