Replace Aspell with Hunspell

[jazzynico]

Related, but not exactly the same: Bug #1049548 Have GtkSpell use Enchant for spell checking.

Inkscape's Text>Check Spelling command relies on Aspell to run. Unfortunately, Aspell doesn't seem to be maintained anymore (last sub-minor revision in 2011), and is becoming very difficult to compile on Windows (with both 32 and 64-bit devlibs).

Hunspell is now used in a lot of applications (including Firefox and LIbreoffice) and its code is still alive. Thus I would probably be an improvement IMHO.

[ScislaC (scislac)]

We would HAVE to get the implementation right though. LibreOffice does it right, FireFox does it wrong. The issue with Firefox for example is that if you have a system that is en_US and the en_GB dictionary is also installed (often the case on linux) it will incorrectly default to en_GB.

[Apteryx (maxco)]

FWIW, there seems to be some development happening again with Aspell; 0.60.7 is being prepared, with the last rc1 released Jan 29, 2017. Based on this sosurce: http://penguindreams.org/blog/aspell-and-hunspell-a-tale-of-two-spell-checkers/ it also seems that Aspell is better at doing spell checking than Hunspell.