Simplified overriding, removed deprecated, forced overriding of response handler

Removed all deprecated methods marked in 1.4.4 and earlier
Made response handlers abstract to force overriding correct methods (with exception on JsonHttpResponseHandler)
Updated Sample application accorindgly
Updated all javadocs, modified retry callback to receive retry number

Modified and updated javadocs, updated method attributes names
Updated threadpool service creating
Completed javadoc for PersistentCookieStore
Merge branch 'master' of https://github.com/loopj/android-async-http

# By mareksebera
# Via mareksebera
* 'master' of https://github.com/loopj/android-async-http:
  Completed javadoc for PersistentCookieStore
  Updated threadpool service creating
  Updated all javadocs, modified retry callback to receive retry number
  Simplified overriding, removed deprecated, forced overriding of response handler