Backport StandardCharsets from JDK 1.7.
Add tests to verify presence of standard character sets.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1615837 13f79535-47bb-0310-9956-ffa450edef68
Remove trailing semicolon.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1615845 13f79535-47bb-0310-9956-ffa450edef68
Fix up javadoc.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1615846 13f79535-47bb-0310-9956-ffa450edef68
Javadoc updates and notes for future selves.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1615847 13f79535-47bb-0310-9956-ffa450edef68
Simplify Loader usage.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1615848 13f79535-47bb-0310-9956-ffa450edef68
Expand on javadoc.

  - Provide some advice for implementors of Appender.
  - Some best practices that we follow (use of manager classes for shared resources, etc.)

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1615849 13f79535-47bb-0310-9956-ffa450edef68