Enhancement: Add the ability to have a flag without the negate option

[GoogleCodeExporter]

Sometimes it's useful to have a boolean flag that doesn't have a negate option.
For example:
DEFINE_boolean 'force' false 'force overwriting' 'f'

It's not needed to have a --noforce for this option as omitting the flag has 
the same result.

We can add an exclamation mark at the end of the flag name to indicate there is 
no negate option for this flag.
In the above eample the new define statement would be:
DEFINE_boolean 'force!' false 'force overwriting' 'f'

The patch already has this for the build in help flag.
DEFINE_boolean 'help!' false 'show this help' 'h'

Original issue reported on code.google.com by pvanderdoes@gmail.com on 9 Jan 2013 at 3:24

Attachments:

• no-negate-option.diff

[petervanderdoes]

See Pull Request #34