Fixed various void-safety issue with recent compilers.

Note that EWF does now require EiffelStudio 7.2, and is compiling with 7.3
Added HTTP_DATE.make_now_utc for convenience.
Extract notification library from the CMS draft application

The new library is located in library/runtime/process/notification.
This allows to use it apart from the CMS.
Rename notification to notification_email
Merge pull request #60 from oligot/notification

Extract notification email library from the CMS draft application
Better support for unicode path and values.

Added WSF_REQUEST.percent_encoded_path_info: READABLE_STRING_8
    to keep url encoded path info, as it is useful for specific component

The router is now using WSF_REQUEST.percent_encoded_path_info
    since URI_TEMPLATE are handling URI (and not IRI)
    this fixes an issue with unicode path parameters.

This should not break existing code, and this fixes various unicode related issues related
   to PATH parameter and path info
   but also any component using file names.

(required EiffelStudio >= 7.2)
Fixing compilation of CMS demo project.
Updated CMS support for unicode.
minor optimization avoiding to create temporary string that might be big
Updated WGI specification to ease future migration to unicode support.
    Use STRING_TABLE, and better interface of READABLE_STRING_GENERAL,
    this way the signature are more flexible for unicode keys.

    Note that for now, unicode environment variables are not correctly supported in WGI
    especially the value of the variables.
    Any layer on top of EWGSI suffers from the same issues.

Better exception handling

+ code cleaning
Removed a few obsolete usages, and benefit from new classes from EiffelStudio >= 7.2
Added HTTP_DATE.append_to...string conversion feature
Made HTTP_DATE.append_...to...string more flexible by acception STRING_GENERAL,
    so it is possible to append to STRING_32 (further more, it avoid potential implicit conversion)
Unicode support for notification_email library
Added notification_email library as official EWF lib.
Updated ecf file as workaround to make autotest works fine.