Shellvars_list: handle backtick variable assignments

Fixes ticket #368
dovecot enchancement and bug fixes

* add mailbox to block_names
* fix for block_args in quotes
* fix for block's brackets upon write
* fixes broken tests for mailbox
* fixes indention
* test case for block_args with "
* fixes broken indention
Use Quote module in dovecot

* use Quote.dquote_spaces for quoting
include only *.repo files from yum.repos.d;
Sudoers: permit underscores in group names

Fixes ticket #370
Yum: permit spaces after equals sign in list options

Fixes GitHub issue #45
Dhcpd: support a wider variety of DHCP allow/deny/ignore statement

The Dhcpd.aug was missing a part of the allow/deny/ignore possible
statement. This commit updates the lense so it supports the list
of options available here

http://www.ipamworldwide.com/declarations-topological/declarations-allowdenyignore.html

Also this bug was preventing a Foreman user to parse the dhcpd.conf
generated by theforeman/dhcp puppet module
Enhance Nagiosobjects lens

This adds support and tests for three additional Nagios
supported behaviors:
- An optional space between the object name and the {
   Example: "define host{"
- An optional indent prior to the closing }
   Example: "    }"
- Whole-line comments that start with ;
   Example: "; This is a comment"

It does not add support for end-of-line comments with ;
* src/transform.c (filter_matches): wrap fnmatch to ensure that an incl
  pattern containing "//" matches file paths

Fixes RHBZ#1031084
Desktop.lns: Support square brackets in keys
Correct locations table for transform_save()

Commit 16387744 introduced a table with locations of temporary, destination and
backup file in various modes as part of the comment for transform_save().  This
corrects two incorrectly listed temporary file locations.

Note that PATH_canon is somewhat misleading, as canonicalized path is always
used when not using NEWFILE save flag, while it is meant to indicate whether
file is created in a directory that contains symlink, or a directory that
contains symlink's target.
Corrections for CVE-2012-0786 tests

- test-put-symlink-augsave.sh - variable $HOSTS_AUGNEW was used to check if
  file was still symlink, while it wasn't set before.  Fix to use
  $HOSTS_AUGSAVE.
- test-put-symlink-augnew.sh, test-put-symlink-augsave.sh - 'test -f'
  dereferences symlink and hence can not be used to check if file is regular
  file or symlink to a regular file.  Use 'test -h' instead.
Yum.lns: simplify code for combinatory logic of list_entry elements
Build: Add combinatorics group
Yum.lns: split excludes as lists (ticket #275)
Build: Add combine_two_ord and combine_two
Build: Add combine_three_ord and combine_three
Sudoers.lns: Allow uppercase characters in user names (ticket #376)
Shellvars: exclude /etc/sysconfig/ip*tables.save files