replace charade by chardet

[smihai]

As the README of charade package suggests

[coveralls]

Coverage remained the same at 92.119% when pulling dbf7d7e on smihai:master into 4bbdc7d on lavr:master.

[lavr]

Although you updated install_requires, I suppose we should provide some fallback here, like this:

try:
    import charade as chardet
    warnings.warn("charade module is deprecated, update your requirements to chardet", DeprecationWarning)
except ImportError:
    import chardet

[smihai]

I agree.
Commits rebased into one

[lavr]

Please, rebase all commits to one commit.
Thanx

[coveralls]

Coverage decreased (-0.04%) to 92.084% when pulling efd4874 on smihai:master into 4bbdc7d on lavr:master.

[coveralls]

Coverage increased (+0.2%) to 92.317% when pulling efd4874 on smihai:master into 4bbdc7d on lavr:master.