MAHOUT-1346

Squashed commit of the following:

(...too long to list... )

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1575169 13f79535-47bb-0310-9956-ffa450edef68
MAHOUT-1438 quickstart tutorial for building a simple recommender

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1575720 13f79535-47bb-0310-9956-ffa450edef68
Mahout-1413: Rework Algorithms Page

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1575732 13f79535-47bb-0310-9956-ffa450edef68
MAHOUT-1434: Dead links on web site

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1575733 13f79535-47bb-0310-9956-ffa450edef68
MAHOUT-1447 ImplicitFeedbackAlternatingLeastSquaresSolver tests and feature

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1576459 13f79535-47bb-0310-9956-ffa450edef68
MAHOUT-1448 In Random Forest, the training does not support multiple input files. The input dataset must be one single file

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1576590 13f79535-47bb-0310-9956-ffa450edef68
MAHOUT-1449 Update the Known Issues in Random Forests Page

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1576604 13f79535-47bb-0310-9956-ffa450edef68
MAHOUT-1451 Cleaning up the examples for clustering on the website

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1577126 13f79535-47bb-0310-9956-ffa450edef68
Updated CHANGELOG for fixed JIRA tickets.

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1577293 13f79535-47bb-0310-9956-ffa450edef68
MAHOUT-1463: Modify OnlineSummarizers to use the TDigest dependency from Maven Central

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1578179 13f79535-47bb-0310-9956-ffa450edef68
Fixing some URLs and cleaning up language

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1578215 13f79535-47bb-0310-9956-ffa450edef68