HR-187 fix : added button class of civicrm 'crm-button', minor css changes for proper display, related webtest modifications

in civicrm, mostly input[type='button'] are used and have a class 'crm-button' is given to span, and input elements.

in civiHR, we have <button> elements, so attributing class='crm-button' renders proper styling like civicrm. 
Apart from this modification, some minor changes in css to show a proper display of button