Bump to version v0.21
Bump to version v0.21

Changelog:
5502a2d iio.h: add some doc about iio_context_clone not working on usb
c240dd7 Upgrade python setuptools for CI
8678898 travis-ci: We don't use "artifacts" so turn it off
eaaf588 travis-ci: remove old branches, so things don't fill up
f9abc28 travis-ci: avoid errors when uploading things to akami
d32fc58 travis-ci: provide an index of artifacts to people can find things.
f03e9ad travis-ci: Only rm old files from one build
c0aab37 travis: save some time by not setting up the host
a024e87 travis-ci: Make sure python is set properly in the lib
e2f46f0 Remove token requirement for sphinx doc build on CI
6bbf792 iiod: Make startup (with Avahi) more robust.
3425601 Remove make install requirement in CI
192fa42 Enable pydoc to be built without library installed
5c86f76 Add support for DESTDIR for python builds
b1d19e3 Fix tag requirement on pypi travis-ci

Robin Getz (14):
      Merge pull request #546 from analogdevicesinc/travis-ci-fix
      iiod: Make startup (with Avahi) more robust.
      Merge pull request #551 from analogdevicesinc/rgetz-make-iiod-start-more-robust
      travis-ci: Make sure python is set properly in the lib
      travis: save some time by not setting up the host
      travis-ci: Only rm old files from one build
      travis-ci: provide an index of artifacts to people can find things.
      travis-ci: avoid errors when uploading things to akami
      travis-ci: remove old branches, so things don't fill up
      travis-ci: We don't use "artifacts" so turn it off
      Merge pull request #553 from analogdevicesinc/CI-python-doc-fix
      Merge pull request #550 from analogdevicesinc/python-setup-fixes
      iio.h: add some doc about iio_context_clone not working on usb
      Merge pull request #554 from analogdevicesinc/rgetz-add-doc-to-clone

Travis F. Collins (6):
      Fix tag requirement on pypi travis-ci
      Add support for DESTDIR for python builds
      Enable pydoc to be built without library installed
      Remove make install requirement in CI
      Remove token requirement for sphinx doc build on CI
      Upgrade python setuptools for CI

Signed-off-by: Dan Nechita <0d348f54705b7a521d732c6906bfe1864d17d562@analog.com>

analogdevicesinc/libiio,analogdevicesinc/libiio,analogdevicesinc/libiio,analogdevicesinc/libiio