[release] version 0.5.8

[release] version 0.5.7

[release] version 0.5.6

[update] version to 0.5.5

[release] version 0.5.4

[update] version to 0.5.3

[update] version to 0.5.2

[fixed] travis ci configuration

update version to 0.5.0

update version to 0.4.2