Add an allowFloat option to the number type

This commit adds an allowFloat option when creating a number.  It
defaults to false, which means that only integer values are accepted for
that number.  If allowFloat is false, float values are still accepted
for min, max, and step, but they are rounded to ints in the constructor.

Signed-off-by: Adam Goforth <code@adamgoforth.com>
Clean up the integer-only number type

- Shorten the typeSpec.allowFloat check.
- Always name the type 'number', even when allowFloat is false.
- Instead of clamping float type spec values, throw an error from the
  constructor.
- Remove some extra whitespace.

Signed-off-by: Adam Goforth <code@adamgoforth.com>
landjetpack-793928: Move promise library in moz-central

Catchup with change to mozilla-central: Switch users of the promise
library to the new location and move tests files.

Signed-off-by: Joe Walker <jwalker@mozilla.com>
integertype-767588: Fix broken 'no match' test

Using 'asdf' as a 'no match' string broke due to the similarity of the
'tsf' command added by the integertype tests. Use 'wxqy' in its place.

Signed-off-by: Joe Walker <jwalker@mozilla.com>
brandname-812762: Remove 'Firefox' from intro string.

Partly we shouldn't have this string in the web version anyway, but also
we shouldn't even have it in Firefox due to other brandings like Aurora
IceWeasel, etc.

Signed-off-by: Joe Walker <jwalker@mozilla.com>
Merge branch 'brandname-812762'