Update For Number Parsing

I ran into a couple of bugs/corner cases related to automatically parsing elements into numbers.  This pull-request fixes the issues that I ran into:  

1. Parsing of white space around numbers are now handled well, e.g. `2,  2, 2  ` becomes `[2, 2, 2]`. 
2. Parsing of decimal numbers are handled in a more robust way, e.g. `.2`, `2.`. 

I updated the regex for float parsing and added a test.