sig

bump patch; remove old python versions

Version bump

chore(version-up): v2.0.3

chore(version-up): v2.0.2

Include python 3.5/3.6 in list of supported versions,
provide signed archives.

MMans as context-mans, drop PY25 region compat, style-changes.

FIX memoryview LEAK(!).

FIX memoryview LEAK(!), simplify region-buffer.

mman as context-manager.

Minor refatcs and styles, add assertion method to check for regions w…

…ith closed mmaps.