Add missing Option::orElse method

[veewee]

The Option::or() method states

     * @note:   Arguments passed to `Option::or()` are eagerly evaluated;
     *          if you are passing the result of a function call, it is recommended to use `Option::orElse()`, which is lazily evaluated.

But there is no Option::orElse() method.

Now there is!

[coveralls]

Pull Request Test Coverage Report for Build 9284818135

Details

• 3 of 3 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.001%) to 97.228%

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Totals
Change from base Build 9280518076:	0.001%
Covered Lines:	5016
Relevant Lines:	5159

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💛 - Coveralls