Document, change description of phlgi_..attributes

Also update relevant bits of abdcmd_fsck, to reflect the broader scope
of the module.
Arcyd: Ignore eol attributes to avoid trouble

In a similar vain to ignoring 'ident' settings, ignore 'eol' settings in
.gitattributes files so that we don't run into edge-cases where a 'bad'
file has been checked in, causing git to want to register changes to the
file in the working copy.

Update phlgitx_ignoreattributes to apply a global setting in
.git/info/attributes of local repos.

Add a test case to verify thtat overriding the eol attribute allows us
to move freely between branches in the event of a mismatch.

Test Plan:
$ ./precommit.sh

Reproduce problem condition, apply fix, use arcyd fsck to fix problem
$ ./testbed/arcyd/test_shell.sh
    .. reproduce the problem ..
    $ printf "\r\n" > badeol.txt
    $ hexdump -C badeol.txt
    $ git add badeol.txt && git commit -m 'add badeol'
    $ echo "* eol=lf" > .gitattributes
    $ git add . && git commit -m 'set eol=lf'
    $ git checkout -b r/master/fixeol
    $ printf "\n" > badeol.txt
    $ git add . && git commit -m 'fix eol'
    $ git push origin master r/master/fixeol
    .. wait for review to be created ..
    $ ./accept.sh
    $ touch blah
    $ git add . && git commit -m 'add blah'
    $ git push origin r/master/fixeol
    .. arcyd is now stuck, thinking it's made local changes ..
    $ cd ../arcyd
    .. change phlgitx_ignoreattributes to ignore eol ..
    $ arcyd stop
    $ arcyd start
    .. verify arcyd is still broken ..
    $ arcyd stop
    $ arcyd fsck
    $ arcyd fsck --fix
    $ arcyd fsck
    $ arcyd start
    .. arcyd is now happy ..