Use polymer for options page

[svenackermann]

• migrate number inputs to paper-input
• migrate dropdowns to paper-dropdown-menu
• migrate checkboxes to paper-toggle-button
• migrate slider to paper-slider
• migrate color inputs to paper-color-picker or paper-input
• migrate radio buttons to paper-radio-button
• migrate hints to iron-dropdown and paper-icon-button or paper-tooltip
• migrate buttons to paper-button
• re-enable special logic for dis-/enabling components and so on
• migrate timer
• check if reload options page on sync/reset is obsolete
• sort categories in tabs
• migrate new features hilighting
• migrate lyrics providers
• consolidate CSS
• auto-select info tab on install/updat
• update documentation