v0.6.0-alpha+3: Add Application Layout styles and directives (#146)

• Add Material Select Searchbox component.
• Material Expansionpanel: Add high density mixin.
• Material Icon: Add back and forward arrows to the list of flipped icons.
• Material Input: Add leading text color mixin.
• Material Popup:
  • Integrate with Angular CSS shimming and remove shadowCssClass.
  • Material design scrollbars by default (instead of the native scrollbars).
  • Add ARIA attributes.
• Material Select: Fix selectable menu item property functionality.
• Material Tree:
  • Add optional row separator borders.
  • Fix dropdown closing on toggle issue.
• Material Tooltips: Add ARIA attributes.
• Improve performance of TreeSelectionOptions constructor from O(n^2) to O(n)
  in the size of listOfOptions.
• Remove uses of 'getBool' in boolean typed inputs.
• Remove use of Compass in SASS files.
• Refactor Angular annotations to inline versions.