add margin() function to composer menu, fixes #343
Merge pull request #876 from obfuscurity/add_margin_function_to_composer

Add margin() function to composer menu
Implements missing minimumBelow() render function

As discussed (for over a year) on issue #255, minimumBelow() is missing
which is odd as it's counterparts are all there. This change
implements that function and adds it to the composer.
Merge pull request #878 from ojilles/master

Implements missing minimumBelow() render function
Overlooked one minimum/maximum discrepancy (fixed on 0.9.x already).
This would leave a confusing documentation :-D
Merge pull request #882 from ojilles/master

Overlooked one minimum/maximum discrepancy (fixed on 0.9.x already).