Command line options parser simplification

In the hosted environment, first argument passed to the main function is a
program name itself, so there is no need to check it for an option string.
Also, this commit contains error reporting improvement - print error messages
into the standard error (stderr).
Default authentication module and background type

Set the default authentication module to the first available one (from modules
which ware enabled in the configuration stage). The order is as follows:
 - pam (--with-pam)
 - password (--with-passwd)
 - md5 (--with-hash)
 - none

The default background type is set as blank with black color.
Module-based input notification

Module-based way to provide input feedback for user. Currently there are
only frame and none (dummy one) modules for input. Frame input module is
simple a port of the previous input indicator with few modifications and
improvements. First of all, frame can be configured (width and colors) via
the application arguments. Secondly it is drawn as a single window, which
removes unnecessary window shadows (provided by the composition manager).
However, when used with the none background module, the effect is not as
intended and this issue should be fixed.

Also main event loop has been refactored. The non-blocking version of window
event check is used only when alock is in the "typing" state, otherwise
loop is blocked until key event occurs.
Support for user's locale based input encoding

Allow to input characters in the encoding defined by the user's current
locale. This commit also introduces support for more sophisticated input
method, e.g. seek input position via arrow keys. However this feature is
not included in the frame input module, due to its design simplicity.
Hashing support via the libgcrypt library

Provide a hash comparing authentication module, which uses libgcrypt as a
backend for hashing algorithms. All hashing functions enabled in the library
are available in this module, even though only few of them are listed.
Remove obsolete internal hashing modules

Since hashing functions are provided by the libgcrypt library, there is no
need to keep internal implementation of hashing algorithms.
Remove not used scons configurations
Source code clean up
Source code clean up (part 2)
PAM authentication module refactoring

Clean up and simplification of the PAM authentication module source code.
For now, when permissions on the PAM database are too restrictive the
appropriate message is shown.
None cursor module simplification / code clean up
Fix hashing support configuration
Use X11 shape extension for frame input module

When X11 shape extension is available, use it to cut out a rectangle
from the interior of the frame window. In such a way, we are able to
make transparent background, while the frame itself is opaque.
Migrating to the autotools build system
Drop support for compiled-in themed cursors

Since we do not support any fancy screen-saver-like animations, why
should we support extra fancy cursors? So according to this rhetoric,
internal (compiled-in) themed cursors and extra xcursor files are
dropped from the code-base.
Update project's origin repository - github fork