Change class changeType to htChangeType

[pnowak]

Description

We need to consider changing class name added by dropdownMenu plugin changeType to much more generic. Maybe htChangeType or something. This class is added to CSS file even when dropdownMenu isn't used.

Demo

http://jsfiddle.net/AMBudnik/keqb1pvc/

Your environment

• Handsontable version:
• Browser Name and version:
• Operating System:

[AMBudnik]

To specify. The change applies to the className that is added to the dropdown menu button.

Simplified demo: https://jsfiddle.net/ed2h7n8g/1/(v8.2.0)