prefs - remove unused pref

This has never been touched or used since the initial commit.
It's using the deprecated pref namespace too.
CHANGELOG - Fill in change history from previous versions

This is as far back as the git history goes.
To go back further we'd have to ask the original authors :)
checkloc - Update script to newest version from main depo

New test case: compare string substitution numbers across .properties files
localization - Fix string substitution in zh-CN

Error found by new checkloc test
About - Add vertical space

Add space and remove newline
so that everyone's name can display without scrolling,
using the default window height.
Localization - Remove 'Firefox' from string

Perspectives is not specific to Firefox,
and we hope to expand to more browsers in the future,
so don't mention a specific browser name here.
Pers_keypress - Convert == to ===
Help - Add Perspectives logo image to page
licenses, MAKEFILE - Move checkloc to extlib folder and note license

Clearly indicate this is an external library we are using
LOCALIZATION - Convert file to markdown formatting
LOCALIZATION - Rename file to 'TRANSLATING'

This file name may be more clear.
README - Copyedit

Add note about translation
Phrase all section titles as verbs,
as that matches an action the reader may want to take.
Pers_statusbar - Unlock the 'About' dialog

It has been ready to use for a while,
and we're no longer requiring all strings to be translated
before unlocking new features.
CHANGELOG - Add new changes for next version

Also cleanup/clarify a few previous changes
Merge pull request #150 from daveschaefer/4.6_fixbugs_part_one

4.6 fixbugs part one