Add support for 6.3.8 which has delete_dictionary_entry and do not use gzipped
pickle. Also give higher priority to symspellpy vs pyspellchecker.
List symspellpy dictionaries by order of cached vs non-cached.
symspellpy 6.3.8 is now the minimum version required and add support for showing
that information to the user.
Also add support for spellcheck libraries that are installed but without dicts.
SymSpell is a great spellchecker which works a lot faster than
pyspellchecker for finding suggestions but is a bit slow at
loading dictionaries (about 15 seconds initially, 2 seconds if
using a cached version).
SymSpell also doesn't come with dictionaries, so the code is currently
using dictionaries from pyspellchecker, so if pyspellchecker isn't
installed, then the user won't see any available dictionaries.
Eventually, would need to have an interface for people to manage
dictionaries for it.
Improves the custom dictionary support by making it more generic
and moving it to the base class. Also makes PyEnchant uses a custom
PWL (Personal Word List) file within manuskript's resources directory
and made pyspellchecker detect available languages automatically.
This modifies the Spellchecker abstraction to add a new dictionary support, with
support for pyspellchecker. It also changes the main UI so that multiple libraries
can be supported and dictionaries provided to the user. The custom dictionary of
pyspellchecker has to be handled manually, and the performance and words of this
library isn't on par with PyEnchant, but at least it works with 64 bits.
Fixes#505
This is in preparation for adding support for additional spellchecking libraries
other than PyEnchant which seems to be unmaintained and does not build in
Windows 64 bit.
