Fixes SI-6400 - Implicit class guide
translated Futures and Promises overview into Japanese.
fixes missing translation. fixes #20
fixes awkward wording. fixes #21
fixes typos. fixes #22
Ported missing Buffers section
Translation to Spanish. String interpolation
Ported missing Additions and Updates section in Maps
Ported missing Buffered iterators section in Collections overview
Merge pull request #124 from eed3si9n/collections/bufferediterators

Ported missing Buffered iterators section in Collections overview
Merge pull request #121 from eed3si9n/collections/buffer

Ported missing Buffers section in Collections overview
Merge pull request #123 from eed3si9n/collections/maps

Ported missing Additions and Updates section in Maps
Merge pull request #119 from scalajp/ja/futures

[Translation to Japanese] Futures and Promises overview
Merge pull request #122 from migue/string-interpolation-translation

Translation to Spanish. String interpolation
Translated Collections overview to Japanese
markdown workaround

For some reason markdown fails with Japanese text sometimes, so turning
this list into html.
fixes scalajp/scala.github.com#26
[Translation to Japanese] String Interpolation overview
[Translation to Japanese] Value classes overview
Localized Overview index page
Adds overview frontmatter