Implements #22836.

Fixes #23391.

The new logo was put together by antonela. Thanks a lot!

Implements the rest of #23383.

The new logo was put together by antonela, and the style changes come
from Raphael Bergmann. Thanks a lot!

Implements part of #23383 (without updating *tile.png files).

Starting with this version, place can contain zero, one, or more
places. Due to the wiki page maintainer dcf, this is on purpose. We
should support that by turning the string into a string array.

In dfdc2c3b we removed three constructors that looked unused, but turns
out that was not the case. Let's just put them back.

This change only changes the source and target version used in Ant
from 1.7 to 1.8 and doesn't make any further code changes. Those will
be contained in separate commits.

Implements #19620 and unbreaks #19730 which apparently contained some
changes related to the diamond operator that require Java 8. Oops.

Improvements include:
 - Replace string concatenations with chained append() calls.
 - Apply diamond operator.
 - Switch to Double.compare() rather than re-implement that logic.
 - Added or removed arguments for printf() calls.
 - Remove unused constructors.
 - Remove unused imports.
 - Avoid NullPointerExceptions in edge cases.
 - Remove redundant initializations or assignments.
 - Remove unnecessary boxing of primitives.

Some catch blocks can be combined using Java 7's `|` operator, others
like `UnsupportedEncodingException` can be avoided by using
`StandardCharsets` constants.

Also document 4 hex character blocks better.

Fixes #22063.

Fixes #23165.

These files are required to compile specification documents from XML
to JSP.

Implements #22827.