phpunit 6

[kokspflanze]

drop php 5.5
added phpunit 6 support
travis update

i will do the ::class job after that PR.

[Xerkus]

@kokspflanze please change branch to develop

[kokspflanze]

@Xerkus done

[Xerkus]

Storage tests have setExpectedException that were not replaced with expectException.
Transport\NullTest expects exception that is not namespaced, might need to be changed too

[kokspflanze]

@Xerkus ohh didnt saw them, these are skipped atm, so build say nothing=(

changed it=)

about the Transport\NullTest these is skipped because it doesnot work on php 7 (Cannot test Null transport under PHP 7; reserved keyword), so dont need to change it, also that namespace doesnt exist on phpunit 5.7.15, so if we change it we need for that the classname hack. i think that is not realy better as the the current solution.

[Xerkus]

grep, or its more modern alternative silversearcher, is your friend

[Xerkus]

@kokspflanze thank you