Umount ISO image before raising SystemExit(1)

When ISO file is not the required DVD install, we should umount the mount point
before raising the exception.

Fix bug https://bugzilla.redhat.com/show_bug.cgi?id=981076
Merge pull request #7 from mopsfelder/umount-iso

Umount ISO image before raising SystemExit(1)
The Great Denaming: remove 'fedup' and 'fedora' where possible

It has been suggested that some users might be dubious of a tool named
'fedup', for reasons I can't begin to fathom.

This commit removes explicit references to the strings 'fedup' or
'fedora' wherever possible; where needed, the variable __package__ is
used instead (which is still 'fedup', but that could be changed by
installing to a different path.)

It also changes all the imports to be relative imports, which is
probably helpful for testing stuff from a local checkout, so that's cool
too.
Fix typo/traceback in pipelogger (#980918)

A variable didn't get renamed - 'thislevel' should have been 'level'.
Whoops.

Thanks to Jeremy Beker <gothmog@confusticate.com> for catching this.
fix some denamed imports in fedup.sysprep

A few lines that should have been "from . import <...>" came out as
"from .import <...>", which is actually equivalent, but looks wrong.

Add the missing whitespace to avoid confusion.
Update TODO.asciidoc
Don't start upgrade if media can't be mounted (#984415)

If the upgrade media can't be mounted, we probably shouldn't start the
upgrade. Therefore, let's put the upgrade media in '.requires' instead of
'.wants'.
disable deltarpm harder (#1005895)

deltarpm has crept into yum core, so disabling the "presto" plugin
isn't enough anymore. Set "deltarpm=0" in the yum conf to turn it off
for real.
Merge branch 'master' into checksig

Merge fixes and denaming from master branch. Conflicts were minor, and
all were caused by the denaming.

Conflicts:
	fedup.py
	fedup/upgrade.py