adapted backend.css+jem.css, REF #138
removed recurrence.js, REF #138
a bit of cleanup

bootstrap.tooltip is not really needed as the bootstrap.framework is
already being loaded within the isis template.
added default value for language field, REF #87
a bit of cleanup

- removed boostrap.tooltip
- changed tooltip of add_category column (export-view)
added language field, REF #87
Revert "added language field, REF #87"

This reverts commit 08ce0f7563fdfdd69698cdf7e5bf19b01007d552.
editvenu/editevent: replaced document.getElement by jquery , removed tooltip seperate loading of bootstrap.tooltip
Merge pull request #143 from jemproject/dev

several changes