If dictionary files have changed, reload them

Store the last modified date of the dictionary files and store it when
the dictionary is loaded. Then each time getDictionary(...) is called,
check the modified date and reload the dictionary if it has changed.
Add analyze and stem methods (analogs to suggest)

The "analyze" and "stem" functions in Hunspell can use almost exactly
the same code as the suggest method that is currently implemented in
HunspellJNA. I just copied the code from suggest and changed the names
of variables and the function to call in Hunspell.

These functions are useful for grammar checks and parsing.
Removed recursion and the checked SecurityException from getDictionary