Fix render regression: khal Padding widh > size

[penguinolog]

Allow to render Padding with GIVEN width > size.
Warn about incorrect size

Fix: pimutils/khal#1334

Checklist

• I've ensured that similar functionality has not already been implemented
• I've ensured that similar functionality has not earlier been proposed and declined
• I've branched off the master or python-dual-support branch
• I've merged fresh upstream into my branch recently
• I've ran tox successfully in local environment
• I've included docstrings and/or documentation and/or examples for my code (if this is a new feature)

[coveralls]

Pull Request Test Coverage Report for Build 7871129273

Details

• 0 of 5 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.007%) to 70.883%

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Totals
Change from base Build 7868637269:	0.007%
Covered Lines:	8777
Relevant Lines:	12465

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💛 - Coveralls