Register 'commonmark/hard_break' as an custom option

So we have all the default parameters in one place,
and not hidden within the renderer function.
Also adapt the 'getOption' function such that it

Register 'commonmark/hard_break' as an custom option

So we have all the default parameters in one place,
and not hidden within the renderer function.
Also adapt the 'getOption' function such that it is able
to retrieve both, leage-commonmark options as well as our
custom registered commonmark options.

show more ...

Implement optional soft break rendering

When the option 'render_softbreaks' is on, use the same
line break characters as for hart breaks.
Also, define the hart break string inside the
'Commonmark.ph

Implement optional soft break rendering

When the option 'render_softbreaks' is on, use the same
line break characters as for hart breaks.
Also, define the hart break string inside the
'Commonmark.php' config, not in the renderer itself.

show more ...

Remove 'default' parameter from function 'getOption'

The underlying 'get' function from 'environment'
->'getConfiguration()'->'get()' does not have a default
parameter any more.

first 2.0 implementation - at least no error

theleague/commonmark 2.0.x compatibility matching

first working version