Add a license

[IQAndreas]

Surprisingly difficult, as there are so many to choose from, and it's difficult find non-legalese explanations for them.

[tskulbru]

Thought I could share some bookmarked links on the matter:

• http://choosealicense.com/
• http://www.tldrlegal.com/compare

[IQAndreas]

Added in f1c655f

GitHub Issues Importer is now released under the MIT License (Markdown-formatted version of the MIT license courtesy of another side project of mine, Markdown Licenses)

[asmeurer]

Good choice.