Rename IDL extended attributes: [ActivityLog], [EnabledAtRuntime], [EnabledPerContext]

Rename IDL extended attributes for consistency with C++ names.

[ActivityLog] => [ActivityLogging]
[EnabledAtRuntime] => [RuntimeEnabled]
[EnabledPerContext] => [PerContextEnabled]

Lots of naming cleanup to code_generator_v8.pm,
a few cleanups to Python.
Also changes to manual EventAliases.in
Otherwise automated (sed) changes to IDL files.

R=eseidel@chromium.org, haraken@chromium.org

Review URL: https://codereview.chromium.org/26657002

git-svn-id: svn://svn.chromium.org/blink/trunk@159420 bbb929c8-8fbe-4397-9dbb-9b2b20218538