Add pipe(2) and pipe2(2)

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
Change indenting in _glibc_constants

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
Add hacky 'backport' of py34 unittest for py27

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
Add tests for constants

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>