Changed workflow for geotagging venues #646
altered mail_plugin

- added html + ip option
- updated query's to new query format
added IP-retrieve/validate function to the helper
removed return from the sendmail-foreach loop
little fixes on new mailer plugin
- added missing texts
- allow events with multiple categories
- handle whitespaces inbetween comma separateds lists
- fix typos in _mailer()
mailer plugin: don't mail ip addresses
Merge pull request #676 from jemproject/plugin_mailer

Plugin mailer fixes and enhancements for 1.9.6
mailer plugin: on empty body text try with ip (related to #676)
mailer: choose name OR username, changed name of changed texts

- depending on component's global setting user's name OR username (loginname) is used
- all mail body have changed as required to have matching "%s" count
- text keys have changed: number of params expected attached (as hex :wink:)
  so en-GB will be used if additional language pack is too old
Merge pull request #682 from jemproject/plugin_mailer

mailer: choose name OR username, changed name of changed texts (related to #676)
Merge remote-tracking branch 'origin/master'
Fixed EL-import: undefined variable $link #688