Fixed missing dependency, picker set as a visible in default

Fixed missing deprecated dependency on highlightable mixin. Removed
highlightable mixin. Picker set as a visible in default.
Styles separated into standalone parts by corresponding component
Added static en titles and names, added livereload to gulp tasks

Static english names for months, days, etc. added instead of ugly
translate strings. Added livereloading of example page when developing.
Added optional Closer, removed overlay and position, changed main class

Presence of Closer depends on existence of `onClose` prop now. Removed
overlay and position, because positioning and make picker modal is issue
for ascendat components. Renamed main css class from `calendar` to
`datetime-picker` because its more obvious that it covers whole picker.
Improved example, now it is more demonstratable.
Reponsibility for a picker visibility moved from inline styles to css class
Bumped version to 0.0.1
0.0.1 - Comes up from old version, adds some improvements, doesnt include locale

- Styles separated into standalone parts by corresponding component
- added static english texts
- added livereload to gulp tasks
- removed overlay as a part of app and setting picker position