help-credits: added word "core"

there are several people helping: translators, devs, testers, members,
testers etc.. so it's probably better to mention Core for the moment.
Weekcal: added call to calendar script, FIX #184
css changes, REF #187
install.sql: changed default value of field version to 3.0.5
added update-sql 3.0.5
events-view: Fix #186, attendees outside grey area
removed span12 classes and replaced it with bs3 classes
module-teaser: some code changes, REF #189
import: fix #197
settings.xml: moved variable img_position

the img_position is at the moment only in effect within the event-page
so it does make more sense to move it to the settings-eventview page.
settings: removed output of img_position
altered jem.css
increased versionnr
increased versionnr
increased versionnr
Merge pull request #198 from jemproject/dev

merge dev files 3.0.5