Added clone method to copy object properties.

implements necessary functionality of jquery extend, being used currently.
Merge branch 'master' of github.com:Imaginea/uvCharts
refactoring utility methods.

Renamed uv.util.extend to uv.util.inherits.
Now using uv.util.extend as object extending utility method.
Merge pull request #22 from priyankadudani/master

Added clone method to copy object properties. Fixed issue #21