Add ability to display custom message on login page

This adds the configuration option to display a custome message on the
web UI login page. It might be used to hint about login credentials to
use or just greet the user.

Fixes #183
Update NEWS file for 0.9.0
Merge branch 'welcome-message'
Add a skeleton example .nipaprc

Add a basic .nipaprc that works together with the default setup of the
nipapd daemon with regards to authentication.

Fixes #199
Back out previous change regarding .nipaprc

Naturally, the .nipaprc file does not belong with the nipap backend but
with the CLI, so we back out this change.

Part of #199
Update example nipaprc file to match default conf

This now matches the default configuration of how nipapd is shipped.

Part of #199
Hack to include .nipaprc skel file

This is a bit of a hack to include the nipaprc file, both as an example
file in /usr/share-somewhere and as a skeleton file in
/etc/skel/.nipaprc.

Fixes #199
Bumped version numbers to 0.9.0
Fix tab completion for entries containing space

Fixes #169
Merge branch 'tab-completion'
Start changelog entries for 0.10.0

First out is the improved tab completion!
Suppress log output from CLI client

Add a nullhandler to the CLI client to handle and suppress log messages
from underlaying pynipap library.

Fixes #200
Toying around with a floating header

Part of #170
Catch more LDAP errors on authentication

In addition to catching the INVALID_CREDENTIALS exception which is
thrown when invalid credentials are entered, also catch
ldap.INVALID_DN_SYNTAX and ldap.UNWILLING_TO_PERFORM which are thrown
when leaving both username and password resp. one of them empty when
authenticating.
Merge pull request #210 from garberg/master

Handle more LDAP exceptions on authentication
Fix the floating prefix list header

This finalises the code on the floating header for the prefix list.
Whenever search results are displayed, we add a header and when the user
scrolls down in the result, the headers "pops loose" and follows the
scorlling at the top of the screen - very nice effect and usefule!

Fixes #170
Merge branch 'floating-header'
Allow empty search in CLI client

Handle case with empty search string and specifically override None and
use a empty search string ('') instead. The former behaviour was useless
as it would cast None to a string ('None') and search for that..

Part of #201
Fix colors on the icons n stuff

Added border to the 'type'-icon to have it align with the toolbox
button. Colors for the type have been revised to new ones.. much
prettier!

Fixes #108
Remove floating header from Add prefix page

When adding the (floating) header to the prefix list page, it was also
added to the Add prefix page for when the user wants to add a new prefix
from another prefix (from-prefix). In that case the same search page and
result is displayed but as the design of the page is slightly different
the new headers didn't line up very well at all, so I removed them.

The idea is to remove the from-prefix mode on the Add prefix page
anyway, as that case should be handled with a option in the toolbox
menu, see #147.

Fixes #170