Remove non-existing NGF states.

NGF client library doesn't include NGF_EVENT_BUSY, NGF_EVENT_LONG, or
NGF_EVENT_SHORT states anymore (they aren't supported by the NGF daemon
anyway). Remove the non-existing states.

[vibrafeedback] Remove non-existing NGF states.
Check for proper libngf version in configure.
Add build dependency version for libngf.

Depend for libngf 0.24 version in spec file.

[packaging] Add build dependency version for libngf.
Merge pull request #85 from jusa/ngf

Use updated libngf client library.