SOC-4173 [Space-Add Application] Mouse Icon is not changed to Hand icon when moving over "Add" button

Fix description: change mouse icon to Hand when mouse over button of class "btn-primary" in CSS.
SOC-4265 | [Contact Information] Hard-coded values of URL.

Fix description:
- Improve select box of Gender and Telephone in Contact section.
- Change default value of URL
SOC-4317: [IE8] Javascript error when deleting letters in Activity Composer

Problem analysis:
* When deleting characters in Activity Composer, triggerOninputMention is invoked to update the text content.
  The property "textContent" isn't supported on IE7 or IE8 browser.

Fix description:
* Only update the text content when currentSelection is valid.
  In case of IE7 and IE8, use "innerText" to get text content.