Add ability to read from IOBase objects

[dlbeswick]

Thanks for your work on this project!

This functionality is particularly useful for decompressing from remote hosts without having to download the file first.

Please let me know if you have any questions or need me to make any changes to make this suitable.

Regards, David

[coveralls]

Pull Request Test Coverage Report for Build 42

• 44 of 54 (81.48%) changed or added relevant lines in 4 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.5%) to 71.429%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
libarchive/adapters/archive_read.py	24	34	70.59%
<!--	Total:	44	54

Totals
Change from base Build 39:	0.5%
Covered Lines:	710
Relevant Lines:	994

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 42

• 44 of 54 (81.48%) changed or added relevant lines in 4 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.5%) to 71.429%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
libarchive/adapters/archive_read.py	24	34	70.59%
<!--	Total:	44	54

Totals
Change from base Build 39:	0.5%
Covered Lines:	710
Relevant Lines:	994

---

💛 - Coveralls