cleanup of Travis CI config file
Squashed '3rdParty/cute/' changes from ac58ea8..b2f2c86

b2f2c86 trigger Travis CI build
e427279 report test duration on the same line for IDE reporter
b0bf02c cleanup of Travis CI config file
b011515 Update README.md
0e90781 unnecessary mutex lock removed
587c547 switched from `catch` to `cute` for unit testing
1cc9fb5 fix includes in the docs
d3f6578 removed `stepper`class in favour of class `cute::tick`

git-subtree-dir: 3rdParty/cute
git-subtree-split: b2f2c86a6f14a258b56b8e845cb19891ce19b0b2
update `cute` library
Merge branch 'master' of https://github.com/Kosta-Github/signals-cpp