devel/py-yappi: Update to 0.94

• Update PORTVERSION and distinfo checksum (0.94) [1]
• Enable USE_PYTHON=concurrent support
• Add NO_ARCH
• Convert DOCS post-install target to OPTION helper
• Add do-test target. PyPI sdist doesn't currently contain tests [1]
• Strip shared library

[1] https://bitbucket.org/sumerc/yappi/issues/7

Based on:

PR: 205113 [1]
Submitted by: Johannes Jost Meixner <xmj chaot net> [1]