Updated access checks, translations, new 'display archive' setting

In addition to changes in 0.8.1rc1 this release candidate contains the following:

• updated access checks for #215 so user cannot escalate himself neither to 'administrator' nor to 'manager'
• added new 'display archive' setting to the Settings>>Users screen. It allows to disable archive for a user. In such case the whole archive panel will not be hidden from the user as well as the API call will be restricted.
• updated german translations to remove 'Unknown overlay' strings for layers, which titles don't have appropriate translations
• now trace recording has new setting called 'time interval' in Settings>>Preferences (in minutes). If set then after that time passes the tail of recorded trace will be cut to make sure that only 'X' minutes of trace are shown
• 'Share' dialog both for Devices and GeoFences objects will be hidden if saving completed with success
• fixed #246 - uploaded marker icon cannot be removed when there are devices with selected icons in profile
• fixed #234 - UI crashed when no overlays are selected in user profile
• fixed #238 - always bring latest position of selected device to the front
• fixed #249 - google maps API was changed and broken compatibility with openlayers. Fixed by forcing use of previous version of google maps API as suggested here

Please note that this is not the final version and it was released due to lots of questions about next release. It does not contain everything I planned to include.