Correct typos.
Merge pull request #246 from joshuapinter/patch-1

Correct typos.
Removed additional underscore in postfix comment.

The suffix includes the initial underscore, if it's present.

i.e. you set the postfix to be something like: `postfix: '_in_cents'`, not `postfix: 'in_cents'`
Merge pull request #247 from joshuapinter/patch-1

Removed additional underscore in postfix comment.
Cleaned up formatting of the helpers section.

- Put into a table to easily see which helper you require.
- Add additional information and subsection for `no_cents_if_whole` configuration option and it's implications.
- Provide examples for quicker understanding of function.
Merge pull request #248 from joshuapinter/patch-1

Cleaned up formatting of the helpers section.