number sanitizing allows scientific notation

I changed src/editors/number.js not to delete 'e' and 'E' used in scientific notation of numbers.
In previous version, if I use a number smaller than 10^-7, it becomes null because in the form 1e-7 becomes 1-7 after sanitizing.
This bug is easily seen in the demo; { "number": 0.0000001 } in JSON Output, then update form and finally becomes { "number": null }