Added ListMetrics method
Removed Namespace from the constructor as not all AWS API method needs it
and for methods like ListMetrics you could need to call the method without
a Namespace to list all available metrics
fixed list_metrics.go in the examples dir
Removes examples because they were causing
tests to fail.
Fix Dimensions and Stats prefixes

There was a dot missing which resulted in this error message when
trying to put custom metrics:

Type: Sender, Code: MalformedInput, Message: Key MetricData.member.1Dimensions.member.1.Name must be all numbers if it starts with an integer
Added the missing '.' in Dimensions marshalling
Merge pull request #58 from levb/master

Added the missing '.' in Cloudwatch Dimensions marshalling
Merge pull request #57 from nabeken/dynamodb-delete-table

Add Dynamodb DeleteTable API support
Merge pull request #56 from viru/patch-1

Fix Dimensions and Stats prefixes
Merge pull request #46 from cfsalguero/cloudwatch_listmetrics

Cloudwatch listmetrics