Refactor: removed use of extend in MagicPen constructor
Refactoring: simplified the handling of lines
Only support prepending lines with a single line pen
Take count argument for newline
Handle empty output when appending
Minor refactoring for clarity
Added method to write a complicated example with a pen
Removed infrastructure to create serializers
The content of a block is now transferred as output entries instead of text
Added size method that returns the dimensions of the output
Simplyfied serializing lines in text mode