fix #4080: user name with >< characters fails to login

Note that the HTML code generated by geocaching.com is invalid if the
username contains a "<". We now support it anyway, as long as the user
name does not contain "</a>".
Merge branch 'release' into upstream
Allow Java 7 constructs
fix #4074: unavailable host prevents pictures from being shown

Moreover, images in geocaches and trackable descriptions are now
loaded in parallel.