Fix #182

[mstackhouse]

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• I have read the CONTRIBUTING document.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

Resolution for #182 and #193

Resolution for #193 involved a couple additional changes. A new regex was created to target number groups specifically. This was applied to str_extract_num(). Documentation and tests were updated.