Add text alignment classes

These are generic helper classes and can be used to align data in table
cells.
Don’t default table cells to tabular numbers

This is typographically incorrect, instead use the .numerical class to
set tabular numbers

Remove text-align from numerical class
- This can be set using the helper “text-right” class
Update right-aligned table example

- Use text-right to right align text within table cells
- Use numerical for numbers which should use equal spacing to make them
easier to compare