Allow non-us-english languages, respect system language default, test cleanup

[hollandjg]

Modifications here were tested on Mac; I don't have another platform on which to test.

Problems addressed:
#15 -- by removing the hard-coded setting of the default language.
Cleaned up spec file to remove the redundant test of the setDictionary
Added a more user friendly setLanguage() which calls setDictionary() but doesn't require any knowledge of the dictionary path (could be useful for solving atom/spell-check#21); also allows more robust testing of behaviour on platforms with non-english default languages.
Rearranged spellchecker file so that functions can be read in order from top to bottom.

Testing required:
Do other platforms have the same behaviour on instantiation of the spellchecker -- namely they set a language default based on the system?

[anaisbetts]

Rearranged spellchecker file so that functions can be read in order from top to bottom.

If you do things like that, can you do them in a separate PR? This makes the PR harder to understand

[anaisbetts]

Do other platforms have the same behaviour on instantiation of the spellchecker -- namely they set a language default based on the system?

No, neither Hunspell nor Win8 do this

[anaisbetts]

Added a more user friendly setLanguage() which calls setDictionary() but doesn't require any knowledge of the dictionary path (could be useful for solving atom/spell-check#21); also allows more robust testing of behaviour on platforms with non-english default languages.

So, while I think the idea of this PR is 💎, the hard-coded default setting is really the "compatibility API" - the API that people should be moving to is instantiating the Spellchecker class, which does support multiple languages properly and has no notion of a "default" language - see #6 for the details

[hollandjg]

Thanks for the feedback! I'll produce a new PR with just the language support changes.

[havenchyk]

Hey @hollandjg, I guess we still need to add dictionaries for every language we would like to check, isn't it?