roverlay/remote/websync: show download status
roverlay/, logging: rotate log files by default

change some logging defaults:
LOG_FILE_ROTATE: false -> true
LOG_FILE_ROTATE_COUNT: 3 -> 5
roverlay/util/common: get_home_dir()
roverlay/fsutil: walk_relpath()

Common functionality for get_fs_dict(), walk_copy_tree().

+ pwd_unexpanduser() function
* pwd_expanduser() uses roverlay.util.common.get_home_dir() now
* get_fs_dict(): don't ignore top-level files unless explicitly stated
roverlay/setupscript/runtime: minor cleanup
install roverlay-query-config

Helper for scripting:

>>> #!/bin/sh
>>> eval $( roverlay-query-config DISTDIR=mirror OVERLAY_DIR=overlay CACHEDIR )
>>>
>>> cd $overlay && do_sth >> ${CACHEDIR}/script.log
>>> cd $mirror  && do_sth >> ${CACHEDIR}/script.log

Also capable of editing template files.
roverlay/depres, rule reader: properly count files

fix a small bug that affects logging only where
SimpleDependencyRuleReader.read() always reports a file count of 0.

Also, remove an unnecessary "self._pool_add is [not] None" check.
roverlay/util/fileio: support xz compression

* roverlay/util/fileio:
** read/write_text_file(): add support for xz
** read_text_file(): catch compression-related errors
                     for the first text line only
** read_text_file(): make sure to close the file(!)
** TextFile: add get_default_compression()
* move SUPPORTED_COMPRESSION dict to roverlay/util/compression
* roverlay/config/entrymap: use roverlay/util/compression
* roverlay/db/distmap: get_default_compression()
roverlay-9999.ebuild: compression USE flags

* bzip2 renamed to compress-config
* the (new) xz flag can be selected to have guaranteed runtime support for xz
Merge branch 'feature/websync-pbar'
add bash completion for roverlay-query-config
fixme note
fix potential python 2 issue

Python 2 checks for __nonzero__(), not __bool__(). roverlay usually relies
explicit checks ("if obj.attr == $expected" or "obj.exists()" rather than
"if object:"), so this is not a major issue.
roverlay: --log-level, --verbose (-v) args

Sets the console log level.