Add DeprecatedOption class.

Used to capture options that are being renamed.
Add deprecated_option to software_spec.

Allows remapping one option name to another and updates build options
and flags accordingly.
formula: add spec deprecated_option DSL.
tab: remap deprecated options in tabs.

If a deprecated option is found in a tab, rename it to the new option.
formula_installer: warn on deprecated options.
wget: deprecate enable-* options to with-*.
wget: update 1.15_2 bottle.