Sequence diagrams: brighten up lifelines

Merge pull request #5 from absltkaos/update_preproc

Make sure that users can still override font settings

Fixed to work with newer plantuml preprocessor syntax

Merge pull request #3 from tbarizien/master

add light style for sequence boxes

Add collections support for sequence diagrams

Merge pull request #2 from eddiechen1008/fix_define_long_to_void_function

fix: change definelong to void function

Add youtube video to readme.

Added sequence, component, use case, state, and object diagram support.

Correct README example command.

4 new styles!

Update readme.

Correct example code