Upgraded HttpCore to version 4.4-alpha1

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@1603442 13f79535-47bb-0310-9956-ffa450edef68
Migrated integration tests to HttpServer from HttpCore 4.4

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@1603443 13f79535-47bb-0310-9956-ffa450edef68
Added static method to close idle connections used by the fluent executor

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@1603444 13f79535-47bb-0310-9956-ffa450edef68
Fixed binary incompatibility with 4.3

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@1603744 13f79535-47bb-0310-9956-ffa450edef68
HTTPCLIENT-1519: Use the original HttpHost instance passed as a parameter to HttpClient#execute when generating 'Host' request header

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@1603745 13f79535-47bb-0310-9956-ffa450edef68
HTTPCLIENT-1521: Added factory method for creation of main exec, which enables subclasses of HttpClientBuilder to override the default implementation

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@1603755 13f79535-47bb-0310-9956-ffa450edef68
HTTPCLIENT-1520: project license link to refer to http://www.apache.org/licenses/LICENSE-2.0.txt

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@1603761 13f79535-47bb-0310-9956-ffa450edef68
Makes no sense to me but hope it will make VMWare happy

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@1603773 13f79535-47bb-0310-9956-ffa450edef68