Include license file in source distribution

[synapticarbors]

It would be helpful to include the license file in the source distribution

[coveralls]

Pull Request Test Coverage Report for Build 210

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 89.505%

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Totals
Change from base Build 209:	0.0%
Covered Lines:	1791
Relevant Lines:	2001

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💛 - Coveralls

[konstantinstadler]

Thanks a lot for that, just updated for accounting for LICENSE vs LICENSE.txt