#73 The caret is not visible in the search field:
- updated search input animation to leverage velocityjs
removed unneeded quotes
replaced toggle buttons animation with a scale / opacity based one
 #74 The cursor should disappear when no user activity is detected
 #75 When the search panel is open the chrome should not disappear:
 - added the option to provide an expression to mtInteractionChrome that can replaces the mouse enter/leave detection by a watching the expression for a true/false value