fixing the problem of having apostrophe in cassandra path for versions < 2.1
properly use single and double quotes to count for single quotes in the CASSANDRA_CONF path
adding extra double slash after -Dcassandra.config option to comply with the update in CASSANDRA-7398
Merge pull request #129 from alaalkhaldi/master

Escaping single quotes in Cassandra path when preparing cassandra.bat and cassandra-env.ps1