Turn the HMMTagger class into a more generic class for tagging tasks

Despite its name, the code of the org.apache.uima.examples.tagger.HMMTagger
class is not totally independant from the pos tagging task.
In addition it assumes that the feature path to update with the result of the
tagging is org.apache.uima.TokenAnnotation:posTag.

We propose to let the possibility to users to specify by parameter the feature
path to set. This parameter is optional. If it is left free, the tagger will
work as usually using the org.apache.uima.TokenAnnotation:posTag as default value.

By the way, we propose to add three optional parameters : InputView, SentenceType and ModelFile.
Since the HMM Learner has got the possibility to specify the view to use to
train a model, we consequently decide to give the same possibility for the
tagger. By default, it works on the _InitialView. It is actually quite useful in practice!

The org.apache.uima.TokenAnnotation type is not the only annotation type which is assumed
to be present in the CAS. Actually, the HMMTagger processes tokens sentence by sentence. It uses the
org.apache.uima.SentenceAnnotation to select the tokens. The SentenceType parameter aims at
letting the users free to specify their own sentence annotation Type. The default value is
org.apache.uima.SentenceAnnotation.

The ModelFile parameter is a concurrent way to the resource declaration way to specify a model.
Left empty, it won t be considered. Otherwise it will predomine over the resource declaration.
When specified, the multiple deployement of the tagger cannot be allowed but in practice for the user it may be easier to configure a parameter through Eclipse.

Two distincts patches will be provided, one for the class and the other for the descriptor.

Future improvement of the class might offer the possibility to create new annotations not only to update existing ones.
Future improvement of the descriptor may dissociate what it is up to the tagger and what it is relevant for the pos tagger...