* IniDBBuilder.h (buildMessage): Define for base class.

* IniDBBuilder.h (buildMessage): Define for base class.
* IniDBBuilderPackage.cc (IniDBBuilderPackage::buildMessage): Define.
* IniDBBuilderPackage.h (IniDBBuilderPackage::buildMessage): Declare.
* PickPackageLine.cc: Pass pointer to package to "pick" throughout, where
appropriate.
* PickView.cc: Ditto.
* install.cc: Ditto.
* package_meta.cc: Ditto.
* prereq.cc: Ditto.
* package_version.cc: Ditto.
(packageversion::pick): Add pkg pointer as second argument.  Display message
where appropriate.
* package_version.h (packageversion::pick): Add pkg pointer as second argument.
* package_meta.h (packagemeta::mesage): Define.
(packagemeta::set_message): Define.
* inilex.ll: Properly return MESSAGE token.
* iniparse.yy: Handle message: keyword.