Replace the ugly arrow shown in Firefox with a custom SVG arrow. Tested
and working in Firefox, Chrome and Edge. The arrow doesn't show in IE, but
the gluon-web-model JavaScript is already severely broken in IE, so we
don't care.
The new code is shorter and uses more readable variable names. It does not
depend on specifically named input fields anymore (allowing to use multiple
maps on the same page), and only uses well-defined interfaces to trigger
revalidation of input fields.
The Map model class allows to add OSM maps to gluon-web forms.
- CGI script and index.html are moved from gluon-web to
gluon-config-mode-core, the script is renamed to 'config'
- gluon-web and gluon-web-model base views and i18n files are symlinked
into the new path
- gluon-web-theme is renamed to gluon-config-mode-theme and installs
directly into the new path
- all gluon-web-* models, controllers and views are moved into the new
path
