[DS-1744] Upgrade to latest log4j
[DS-1832] Proxy configuration set in system properties if empty
DS-1757 Missing images in mobile theme

Removed link to mobile-default-thumbnail.png and changed to default-thumbnail.png which already existed.
Added contextPath
DS-1756 Wrongly aligned text on mobile theme

Removed margin-left: -35px; which pushes "There are no files associated with this item." over to the right. I tested this in firebug.
DS-1878 make search URL recognize Lucene/Discovery in mobile theme
DS-1881 Remove filter button in XMLUI Discovery filters deletes all "New filters"
DS-1816 add missing DSO type to DRI (focus.containerType)
DS-1879 Do not require ADMID for bundles in METS
Fix for DS-1867. Ensure native2ascii call uses 'root.basedir' and not 'basedir', so that it also works from submodules (e.g. [src]/dspace). Also some minor cleanup of POM.
DS-1890 correct scope logging of searches

logged scopeId and scopeType properly.
throw missing exception when batch importing using BTE via admin UI
change default BTE configuration for CSV and TSV data loaders
Fix a bug that brings down the webapp container.

Instead of using System.exit() the method addItems now throws an
exception that can be handled higher in the calling stack, or will
terminate the thread.
addBTEItems rethrows BTE exceptions
Update dependency to the latest BTE release
Exclude Bootstrap from license check, restore stock notices
[DS-1893] Get page refresh after adding a value in the submission forms clears all metadata in XMLUI
[DS-1833] Collection content source harvesting test does not work with ORE
DS-1897 Upload Progress bar only doesn't show progress
Merge branch 'dspace-4_x'