Merge tag '1.4.0' into develop

Release of 1.4.0
Preparation for new development cycle after release 1.4.0
Add flag no-ff to feature finish.

This gives the ability to never fast-forward a merge, even when it's
only one commit.
Merge tag '1.4.1' into develop

1.4.1
Merge tag '1.4.2' into develop

1.4.2
Version bump 1.5.0
Fix the flag --no-ff

I should take my time testing and no rush anything.
Anyway, it works now.
Bugfix: Error in a long flag name for release finish
Function _flags_itemInList refactored.

The function no longer makes use of external commands, making it a bit
faster.
Add functions for overriden flags.

Add the functions to override a voolean flag and also a function to
check if a given value is a valid boolean.
Add override ability
Add override ability
Add override string function
Add override ability
Add override ability
Add override ability
Refactoring of functions.

Refactor the function to override the flags to make them more like the
other functions in the program.
Version bump 1.5.0-dev.17
Merge branch 'feature/set-flags-default-by-env' into develop
Quote the string to check.

When the variable is set to an empty string, it needs to be in quotes.