Added threshold for not rounding numbers

Fix #314
Due to the nature of the utils file, it is unreasonable to import core.js due to circular dependency issues. Thus, a new argument `threshold` has been added to `prettyNumber(value, threshold)` which defaults to null. This argument can be passed in from the `ui` .js files in which importing core.js is fine.
 
Signed-off-by: Sheik Hassan <solergiga@yahoo.com>