v2.2.5 release (#586)

Merge pull request #566 from yahoo/leewyang_v2.2.4

v2.2.4 release

Merge pull request #553 from yahoo/leewyang_v2.2.3

update setup.cfg too

Merge pull request #542 from yahoo/leewyang_sd

migrate build from travis to screwdriver

Merge pull request #512 from yahoo/leewyang_v2.2.1

v2.2.1 release

Merge pull request #504 from yahoo/leewyang_v2.2.0

v2.2.0 release

Merge pull request #497 from yahoo/leewyang_v2.1.3

prepare v2.1.3 release

Merge pull request #491 from yahoo/leewyang_v2.1.2

v2.1.2 release

Merge pull request #489 from yahoo/leewyang_v2.1.1

v2.1.1 release

Merge pull request #484 from yahoo/leewyang_v2.1.0

prepare v2.1.0 release