Update Readme

[BraianS]

Proposed changes

Update the svg and the href link of travis-ci because they are changed, and remove the david-dm links because they are broken,

Screenshots (if appropriate) or codepen:

The current version

The new version is correct and clean

Types of changes

• Bug fix (non-breaking change which fixes an issue).
• New feature (non-breaking change which adds functionality).
• Breaking change (fix or feature that would cause existing functionality to change).

Checklist:

• I have read the CONTRIBUTING document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.