CheckStructure: fix numeric else-clause detection

Two related errors are fixed here:

The documentation always told that when numbers were used as
else-clauses or as structure definitions a positive number would mean
PASS and a negative would mean FAIL. However, the code always treated
non-zeroes as PASS and zeroes as FAIL. I changed the documentation to
say what the code always did.

The code detecting numeric else-clauses wasn't detecting negative
numbers rightly. It's fixed now.

This problem was brought to my attention by Uwe Satthoff. Thank you!

Signed-off-by: Gustavo L. de M. Chaves <gustavo@cpqd.com.br>
Fix some Perl::Critic warnings

Signed-off-by: Gustavo L. de M. Chaves <gustavo@cpqd.com.br>
v1.20

        In CheckJira, the PROJKEYS in a 'projects' option may now have
        spaces around the comma separating project keys.

        Fix UpdateConfFile. It was considering only the fist
        added/updated file in a commit for updating.

        Fix CheckStructure numeric else-clause detection. Also, fix
        its documentation to say that negative values are also treated
        as true. Only zeroes are considered false. (Thanks to Uwe
        Satthoff for bringing this to my attention!)
UpdateConfFile: implement option 'remove'

By default, if a file is deleted in the commit, nothing happens to its
copy in the repository. If one wants to have the copy removed from the
repository when the file is deleted, there's a new option 'remove'
that should be set to true.

This feature was suggested by Uwe Satthoff. Thanks!

Signed-off-by: Gustavo L. de M. Chaves <gustavo@cpqd.com.br>