more deployment fixes.

Merge pull request #436 from sjhewitt/sjh-python38-3

Another try at getting python3.8 builds on travis

fixing integration test

fixing duplicate obj files.

1. fixing missing dep for Python 2.7

2. updating MANIFEST to try fix source tarball uploaded to pip.

improving docs.

minor version bump

Fixing broken travis/appveyor to proper test memory-leaks #398

Merge branch 'master' of github.com:nmslib/nmslib

bumping up the version.