Reworked logistic regression classifier

Merged PR #1227 to master and reworked logistic regression module to conform with new machine learning framework architecture.
this is very minor, but since we are trying to make things consistent, please, replace 
<pre>
&lt;opencv2/modname/modname.hpp&gt;
</pre>
to
<pre>
&lt;opencv2/modname.hpp&gt;
</pre>