Bug/skip date with output

[TheFrok]

I reopened the PR because it was stuck in an odd state.

The changes are to the part that searches for existing output files.

-- From the description of the original PR (#313):

• Fixed an error in the function that searches for dates without output
• added skip as an option to the configuration
• added the correct regex for file names to the example config and set it as a default value
• removed unnecessary fields from the minimal config example

[TheFrok]

Does anyone knows why github thinks the travis build are still running? @cjer

[OrBin]

Does anyone knows why github thinks the travis build are still running? @cjer

Just a bug in GitHub, I guess. An administrator can merge even without the checks passing, so don't worry.

[cjer]

@TheFrok @OrBin Can we merge this?

[TheFrok]

I think we can merge. The only thing is the log discussion, which is kind of a taste thing that I'm not sure about