cut down on duplication to pull various domain settings
revert to unlocalized content sets everywhere

This provides a more consistent view of merged files when compared
between pmerge/portage output and the vdb. Also, this is needed to allow
settings such as COLLISION_IGNORE and UNINSTALL_IGNORE (which both
include '/lib/modules/*' by default) to work properly on systems where
/lib is a symlink without having to go through the process of resolving
all the listed paths.
don't apply stable use mask/force settings to unstable systems
add support for UNINSTALL_IGNORE (see make.conf man page)
use logger.warning instead of logger.warn which is deprecated
conditionally replace deprecated configparser readfp method with read_file
remove deprecated os.stat_float_times calls and related functionality

Python has defaulted to floating point timestamps since 2.5 and the
os.stat_float_times method is deprecated in 3.3 and later.
use tempfile.mkstemp instead of mktemp
explicitly close files after usage is complete

Python 3.4 throws a ResourceWarning when a file object is destroyed
without having been explicitly closed. This fixes many of the simple
cases, but not all of them.