Bunch of PureMVC improvements and bug fixings

[expobrain]

Fixed som bugs in the implementation of some interfaces and classes and added little improvements on the code and unit tests

[tekool]

I'll make a quick code review with a colleague of mine in the day. Keep you informed, but a first glimpse at what you made seems pretty needed, thank you.

[expobrain]

Ok, done here https://github.com/expobrain/puremvc-python-standard-framework/commit/bb6ac2d22640796169c8c7a1574f1df7dacb3cb6, with a brand new unit test

[tekool]

My colleague who knows Python very well validated your work and tells me that your choices were all the smart ones.

[expobrain]

Thank you sir, but I did only my job :-)

What about increasing the version number to 1.2.1?

[tekool]

Just make any changes you think useful, integrating changes with Github is really painless. Version number must be edited by you in the version.txt first. I'll report it in the Python port home page if Cliff is agree to.