Merged with gms-chris
Merge pull request #4 from gms-chris/master

Finish of initial work on plugin
Various enhancements on the ssh transfer backend

- reorganisation of the default config, with example
- return success code in the ssh transfer
- allow to use a callback to transform the logon name from roundcube.
Continued the SSH backend for vacation

Added regular expression search/replace to the logon name
Change the remote path with the patterns for regex
Fixed vacation plugin

Hour selection in the vacation plugin is not working. Writing only the date for now.
Added a new search_highlight plugin

Added a plugin to highlight the words searched in the message
Fixed HTML text highlighter

Used a good example of php code to hightlight searched words without corrupting HTML tags
Implemented hours selection in the vacation plugin

Implemented the different cases for the vacation system
Restrict the hours to a raisonable range

Allow admin to restrict the selection of working hours in a raisonable range
correct filename and add 'host' for managesieve

 - Fixes Issue #7
Fix logic error and copy/paste typo
Managesieve: error checking and RC 0.8.x support

 - Checked with RC 0.8.4
 - Fixes Issue #5 & #6