Update Thumbnails.pm

MIME type for generated thumbnail defaults to image/png, but jpgs are generated. Changed default MIME type and documentation.
Merge pull request #68 from QUTlib/master

small pod change in lift_embargos
Applying rolled-up dist fixes (nearly done)
debian packaging scripts
Make Debian scripts respect configure

New configure parameters:
--with-debian-stable
--with-debian-unstable

Fixed debian install scripts trashing the eprints user (blocking upgrades).

Use --prefix, --with-user and --with-group to set debian locations.
Fix uninstall not triggering due to wrong SIG path
Replace named entities with numeric equivalents to workaround libxml2 issue #69
To help alleviate the issues caused by the libxml2 bug (https://bugzilla.redhat.com/show_bug.cgi?id=863166), replace named entities with numeric equivalents - this will at least mean new EPrints installs with the bad libxml2 version don't immediately run into a problem.
adds debug methods:
EPrints->trace() - show a non-blocking call trace
EPrints->assert( CONDITION ) - evaluates the condition and show a call trace if false
'Spanish' is the correct term in English
Fixes #71
Publish more metadata via Dublin Core

id_number => relation
language => language
document.license => rights
document.language => language

This should increase the likelihood of a DOI making it into the Dublin Core.
Merge branch 'master' of github.com:eprints/eprints
Fixes #72
Merge branch 'master' of git@github.com:eprints/eprints
Fix Drag-and-Drop

When a file is dragged to the Upload component create a new document.

When a file is dragged to an existing document resume uploading (if the file
exists), otherwise add it.

Support partial file writes over CRUD.
Merge branch 'master' of github.com:eprints/eprints
A bad symlink will still -e, overwrite in epm linking
Fixed autocomplete drop-down misplacement

Fixed 'false' appearing in Internet Explorer - the Scriptaculous overlapping
fix was doing something odd.

Simplified the autocompleter a bit - just use 'absolute', no need to use
position cloning.
Fix upgrading changed repository files

DataObj::EPM::enable() would throw an error if a repository file already
existed and differed to its checksum.

Correct behaviour:
DataObj::EPM moves the modified file to .epmsave
Screen::EPMC recognises the .epmsave and replaces the new version with
.epmsave, saving the new version as .epmnew

Work-around:

Before upgrading, disable the package, upgrade and then re-enable it.

Reported by Samuel Pearce @ Open (CORE)
Fixes #74