Correctly process the situation when squashfs file isn't there
Made error message more verbose (as suggested by Clem)
Added option for automatic login

The user configuration screen now has a checkbox for autologin.
If checked, post installation sed scripts are run, covering all
the most used display managers.

Closes #18
Get current xkb layout more reliably
Query GeoIP City database for time zone as well
Parse xkb rules only once using xml.etree.ElementTree
Slightly more concise assign_keyboard_* callbacks
Defer keyboard preview generation for smoother scrolling
Merge pull request #37 from kernc/autologin

Added option for automatic login
Merge pull request #39 from kernc/default_timezone

Select default timezone based on IP address
Merge pull request #42 from kernc/kbd_switch_delay

Annoying delay when switching keyboard layout
Merge pull request #31 from monsta/patch-4

Correctly process the situation when squashfs file isn't there
Grammar & style of i18n labels

Mostly very minor grammar and/or consistency fixes in
translatable labels, full sentences in help labels, etc.
Two label asignments are replaced with GTK+ stock items which
results in correct translations, standard mnemonics, optional
button icons, ... These two are `GO_FORWARD` and `APPLY`. The
latter replaces "Install" on the installation overview screen.
Guess timezone by IP, else by country from IP, else by language

Fixes problem introduced in #39.
Merge pull request #43 from kernc/default_timezone2

Guess timezone by IP, else by country from IP, else by language
Use isoquery for countries list
Use isoquery for languages list
Use system supported locales for language selection screen
Use custom flags for Esperanto and Interlingua
Make language selection list sortable by columns

Some users of "obscure nationalities" may not know what their
language is called in English, yet they may more easily recognize
it by country or flag (when sorted). Can't hurt.