Install gettext.translation based on locale else lang else English
Fixed a pair of typos
Merge pull request #52 from kernc/gettext_translation

Use gettext.translation for locale else for lang else hardcoded English
Merge pull request #54 from iturralde/fix-typos

Fixed a pair of typos
Simplified timezone map pixel calculation
Gtk dialogs in a separate module
Show ErrorDialog on unhandled exception
Everything timezone in a separate module
Fixed many timezone cc.png colors
Replaced useradd with adduser, added more default groups
Use streamer for webcam face capture

A simple small utility, compatible with V4L, replaces
OpenCV, the code for which, as used, was deprecated anyway.
Replaced map radio-button-style dot with a red "maps" pin
Fixed wrong click-selection on tz map when installer resized
Preview current local time on timezone selection screen
Replace combobox with button and menus for timezone selection
New timezones background is a satellite image
Timezone map daylight overlay
Allow installation to more than one drive

This commit somewhat overhauls the partition selection screen.
It introduces the following changes:

* parted binary is used for easy, optimal partitioning;
* the HDD selection screen is no more,
* instead, all attached drives (sans the rootfs one) are shown
  in the disks (partitions) treeview,
* and there is a button 'Expert mode' for the "custom mount onto
  /target instructions";
* all python code related to partitioning is in the new
  partitioning module;
* the colorful partitions webview is a standalone HTML file in
  usr/share;
* plus other related minor simplifications, additions & fixes.

Also closes #21.
Moved everything partitioning related into partitioning module
i18n of program and slideshow

This commit includes:

* i18n of slideshow in po4a system (with Debian-recommended
  paths),
* locale translations in project locale directory
  /usr/share/locale/live-installer/,
* a .gitignore,
* somewhat simplified slideshow.py and related code,
* slides now enumerated HTML filenames in appropriate dir,
* somewhat improved and updated slideshow text, partially joined
  with ubiquity's mint-slideshow texts,
* only some four "fuzzy" translations per language (kind to
  your translators),
* complete 'sl' translation as the contributor speaks it perfectly,
* removed (any reason for) en_GB and en_AU -- lots of empirical
  evidence shows only two languages require additional locale
  specified: pt and zh,
* Makefiles for building/updating translations (target 'update'
  for updating program labels while slideshow is auto-updated on each
  build, just keep them *.po files in sync).