refactoring: add missing final
fix #3262: c:geo does not handle inline images
Merge branch 'release' into upstream
Merge remote-tracking branch 'upstream/issue-3260' into release
Merge branch 'release' into upstream
Use Apache commons IOUtils rather than our own
Use Base64 class from our HTTP library

The Android one is available from SDK level 8 only and we require
level 7 for c:geo.

Related to #3262.
Merge branch 'release' into upstream

Conflicts:
	main/src/cgeo/geocaching/network/HtmlImage.java
Add comment about using streaming version of base64
refactoring: do not create explicit handlers when not needed

When no information is to be carried to the handler, if the handler is
called from one place it is simpler to use runOnUiThread rather than
to construct an explicit handler.
Experiment with concurrent execution