Japanese program translation update

Closes: 763033
allow fetcher setup without directory creation

apt-get download and changelog as well as apt-helper reuse the acquire
system for their own proposes without requiring the directories the
fetcher wants to create, which is a problem if you run them as non-root
and the directories do not exist as it greets you with:
E: Archives directory /var/cache/apt/archives/partial is missing. -
Acquire (13: Permission denied)

Closes: 762898
cleanup partial directory of lists in apt-get clean

Not really the intended usecase for apt-get clean, but users expect it
to help them in recovery and it can't really hurt as this directory
should be empty if everything was fine and proper anyway.

Closes: #762889
allow options between command and -- on commandline

This used to work before we implemented a stricter commandline parser
and e.g. the dd-schroot-cmd command constructs commandlines like this.

Reported-By: Helmut Grohne
replace c-string Mode with c++-string ActiveSubprocess

A long-lasting FIXME in the acquire code points out the problem that we
e.g. for decompressors assign c-string representations of c++-strings to
the Mode variable, which e.g. cppcheck points out as very bad.

In practice, nothing major happens as the c++-strings do not run out of
scope until Mode would do, but that is bad style and fragile, so the
obvious proper fix is to use a c++ string for storage to begin with.

The slight complications stems from the fact that progress reporting
code in frontends potentially uses Mode and compares it with NULL, which
can't be done with std::string, so instead of just changing the type we
introduce a new variable and deprecate the old one.

Git-Dch: Ignore