1.0-3:  Add binary operators & and | as shorthands for unionRSiteSearch 
and intersetRSiteSearch

1.0-2:  Add hits function

1.0-1:  Fix a minor bug in unionRSiteSearch.

1.0-0:  Add unionRSiteSearch, intersectRSiteSearch and PackageSum2

0.1-6:  Add function PackageSummary to compute the summary
previously done inside RSiteSearch.function, convertinng it
to a data.frame and adding the Date.

0.1-5:  With zero hits, RSiteSearch.function still returns
an object of class c('RSiteSearch', 'data.frame');
previously, it returned only a data.frame with zero rows.