TASK - Implement Player Properties

[mfreidel]

This will probably be a fairly large task and may need to be broken up into smaller pieces before converting into a tracked issue.

Implementing basic player properties is mainly defining a proper health and damage system. Code should consider the ability to add additional properties in the future.

Planned Milestone: 0.3.x

Pre-flight Checklist

Verify all before submitting

• I have performed and documented some basic research and planning before opening this task.
• This task implements a new core feature, or substantially alters an existing one.
• I have confirmed that this is not a duplicate task.
• I have confirmed that this task is not already being worked on or completed.
• This issue has an assignee.
• This issue is assigned to the learn2shmup project.
• This issue is assigned to the appropriate milestone in GitHub.
• This issue has appropriate labels to identify components this may alter.
• I have read, selected, and verified the above checkmarks accurately.

Sub-tasks

Smaller individual tasks required for completion:

• Implement feature(s)
  • Any smaller components?
• Any extra steps?
• Write documentation and/or notes
• Manual testing

Planned procedure

Chronological list of planned work:

1. Step One
2. Step Two

Task research, planning and notes

If your pre-flight research/planning notes are not with your code, then paste
them over the contents of this section.
If they are with your code, then delete this text except for the following line:

Pre-flight notes are with code