Reformat all files with clang-format

[sigiesec]

We have a .clang-format file but over the past 1.5 years several deviations from the defined formatting have evolved. This reformats all files with clang-format to reestablish consistent formatting.

[coveralls]

Pull Request Test Coverage Report for Build 326

• 61 of 63 (96.83%) changed or added relevant lines in 2 files are covered.
• 5 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.9%) to 85.787%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
zmq.hpp	43	45	95.56%

Files with Coverage Reduction	New Missed Lines	%
zmq_addon.hpp	1	97.08%
zmq.hpp	4	82.66%

Totals
Change from base Build 324:	-0.9%
Covered Lines:	676
Relevant Lines:	788

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💛 - Coveralls

[gummif]

Looks good

[sigiesec]

@zeromq/core Can someone merge this, please?