Fixed the Cannot read property 'host' of undefined issue when only on…

…e site is available

fix: Fixed the issues with error handling

Changed the way the error handling is done and fixed the issue where the task is not failing even if
there are exceptions thrown

Fixed the issues in HTML report generating.

chore(task): Updated the vss-extension file

Changed the color of the task info page header in the marketplace

fix(report): Updated css style in the HTML report

fix(report): Update the styling of the HTML report

Closes #6

fix(task): Fix the bug when generating the HTML report

When generating the HTML report, if an alert does not have any instances available to it the task
throws an exception. Fixed the issue by checking to see if any instances are available.

Closes #5

fix(task): Fixed the reference issue to the owaspzapscan.js file

chore(build): Updated travis.yml file

File extension updated in vss-extension.json