HPCC-9200 Install improvements

Allow side by side installs
Insert Add/Remove Programs entry
Check for previous version

Signed-off-by: Gordon Smith <gordon.smith@lexisnexis.com>
Merge pull request #121 from GordonSmith/HPCC-9200

HPCC-9200 Install improvements

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>