Update readme.md

Removed `:*` from require
Merge pull request #1575 from verschoof/patch-1

[skip ci] Update readme.md
Update 12-ParallelExecution.md

Fix some small issues with in code examples
Merge pull request #1576 from zmilan/patch-1

Update 12-ParallelExecution.md
Update 12-ParallelExecution.md
Merge pull request #1579 from ajo-silent/patch-1

Update 12-ParallelExecution.md
Add missing quote in example
Update .travis.yml
capital_P_dangit
Merge pull request #1582 from xwp/feature/capital_P_dangit

capital_P_dangit
Merge pull request #1580 from drewhammond/patch-1

Add missing quote in example
Update README.md
Fixed spelling error
Merge pull request #1586 from leepownall/patch-1

[skip ci] Fixed spelling error