LWSHADOOP-584: Add "how to contribute" section (#15)
LWSHADOOP-584: Add "how to contribute" section (#15)

* LWSHADOOP-584: Add "How to contribute" section to README file

* LWSHADOOP-584: Fix list items enumeration

* LWSHADOOP-584: Fix size header of "How to contribute" section

* Copy edit README changes

LucidWorks/hadoop-solr