Spell checker for Sylpheed 0.6.3

This is a backport of the spell checker found in Sylpheed 0.6.2claws. 

1. Requirements
2. Configuring Sylpheed
3. Usage
4. Known problems

1. Requirements
---------------

It uses the Portable Spell Checker Interface Library pspell 
(http://pspell.sourceforge.net), version 0.12.2 or newer.  You will need
also the actual spell checker.  There are two alternatives : 
1. ispell, which is found on quasi every distribution.  You have then to
install the pspell-ispell module found at the pspell site.
2. aspell, (http://aspell.sourceforge.net).  This spell checker must be
installed after installing pspell.  The version tested is .33.7 alpha.
It has three different suggestion modes (fast -default- , normal, bad 
spellers), has the ability to learn from mistakes (default).

2. Configuring Sylpheed
-----------------------

Spell checking is enabled if you configure sylpheed appropriately. 
Add the option '--enable-pspell' when configuring. E.g.

./configure --enable-pspell

The configure script need 'pspell-config' in your path.  If it is in
weird places, use '--with-pspell-prefix' to tell the path to
pspell-config.  E.g., if pspell-config is really /foo/bar/pspell-config,
then use :

./configure --enable-pspell --with-pspell-prefix=/foo/bar

If you have problems with not found includes or libraries, check first
where these are located, and add either options
'--with-pspell-includes=/foo/bar/include' or '--with-pspell-libs=/foo/bar/lib' 
as appropriate

Configure script summarizes the options compiled in.

Then proceed as usual, with 'make' and 'make install'.

3. Usage
--------

After successful compiling, you need to tell sylpheed where your
dictionaries reside.  First run 'pspell-config pkgdatadir' on the
shell to get their path. 

Then run sylpheed and go to Configuration -> Common preferences -> 
Compose.  Check the box 'Enable spell checker (EXPERIMENTAL)' and 
use the file selector ('...' button) to select the path where 
the dictionaries reside.  Within the file selector, go to that 
directory and select *any* file in the file lists.  Click ok. You should
then be able to select your default dictionary.  

When composing, misspelled words are highlighted.  Click on any
highlighted word with the right mouse button to get a list of
suggestions.  You can also accept the highlighted word to the session
dictionary (equivalent to an 'ignore' option of other spell checker), or
you can add it to you personal dictionary.

If you click with the right mouse button every where else, or if you
shift-right-click even on a misspelled word, you get the configuration
menu.  'Check all' highlights all misspelled words.  You can also change the
dictionary.  You can change the suggestion mode and toggle the learn
from misktakes features (useful only with aspell).

4. Known problems
-----------------

The only known problems until now are configuration and compilation
problems  due to libtool interaction with pspell. 

If you do not compile pspell/aspell/pspell-ispell yourself, you need to
install them with their devel packages.

Pspell work with dynamic linking of libraries and thus uses the libltdl
library of libtool.  If you have weird problems when configuring showing
'libtool', chances are the libtool used when compiling the pspell
package is not compatible with what you have on your system.  The best
solution, is to install the latest libtool AND compile yourself pspell
package.  I can't help more than that in this issue.

After successfully compiled and used sylpheed with spell checking, 
the same problem can appear if you upgrade your libtool to a version
which libltdl is incompatible to your older one.    The
symptoms are a crash when starting to compose.  Disabling spell checking
avoids the problem. The solution should be to recompile pspell.