Refactoring of container loader.

- Overall simplification
- Define the Loader API
- Adds a lot of tests
Adds webapp2 as a requirement, to fix test suite.
Internalize cached_property decorator and removes webapp2 dep.
Simpler factory getter, no need to reimplement cache on top of cached_property
Fix builtins implementation problem, now uses __builtin__ instead of __builtins__ (cf https://docs.python.org/2/library/__builtin__.html and http://stackoverflow.com/questions/1184016/why-builtins-is-both-module-and-dict)
Test coverage enhancement and reference implementation for xml loader.

- Exceptions for basic types are now closer to bare python type cast errors (ValueError instead of TypeError).
- <reference> tag now works again as expected (may still need advanced testing).
- Adds tests and pragma no cover annotations.
- Adds a base TestCase class which logs to DEBUG level the test methods called.
- Removes unused test.
Adds test for container parameter setters/getters. Fix float test in simple tests which may fail on python 2.7 at least, according to travis builds.
Looks like the container api for multi get/set is not yet very polished, this commit gets something up and running but multiget/set should get a further/deeper look/think.
[Tests] add simple service definition test using builtin module (os.path)
[Doc] bootstrap sphinx dir structure
Add flags to configuration so we can indicate that a collection should be lazy loaded or not. The set_parameter vs define logic should be grouped to simplify this.
[Tests] Fix output format so we retrieve the flags in tests. This API should not be considered stable yet.
Merge remote-tracking branch 'remotes/origin/dev-refactoring-loader'

Conflicts:
	rdc/dic/definition.py