README: Remove indication on the XPI for downloads.

Signed-off-by: Rogério Brito <rbrito@ime.usp.br>
README: Add more text and the rationale for this fork.

Signed-off-by: Rogério Brito <rbrito@ime.usp.br>
Change the name of the extension.

Signed-off-by: Rogério Brito <rbrito@ime.usp.br>
package.json: Change the ID of the extension.

I have only changed one character that seems to be valid. If it is not, then
I will certainly be informed of that.

Signed-off-by: Rogério Brito <rbrito@ime.usp.br>
package.json: Add lRem and jblanche to the contributors field.

Signed-off-by: Rogério Brito <rbrito@ime.usp.br>
package.json: Set me as the 'author' (for lack of better name).

Signed-off-by: Rogério Brito <rbrito@ime.usp.br>