indeo4: add missing Haar and slanted transforms

That involves fixing INV_HAAR4() macro and changing it to work with different
input and output like INV_HAAR8() instead of in-place transform.
indeo4: reuse context block VLC for band instead of defaulting

Currently if no custom block VLC is specified for band, a default block VLC
will be used, while the global block VLC stored in the context should be used
instead.

This fixes decoding of one sample I have.