Support integers and booleans

A lot of settings in CloudFormation are declared to accept only strings, but they, in fact, accept integers nad booleans. All my templates have numbers as integers, not as strings, and I've never had issues. Unfortunately, now, after I'm finally using troposphere, I need to use strings as you guys are strict about this.

Is it possible to enable a mode where either:
- you convert everything to strings on your end;
- you don't convert and accept integers and booleans natively.

Start by tracing where troposphere enforces string-only settings and compare that behavior with the CloudFormation templates described here. Define one consistent mode—converting values to strings or accepting native integers and booleans—and verify representative templates with both value types.

Written by the indexing model from the issue text.