Evaluate Python 2.5.x compatibility.

[sopel]

This has been triggered by evaluating vert.x:

Vert.x doesn't seem to properly work with Jython 2.7.x yet, only with its predecessor Jython 2.5.x. This is obviously more a Jython issue, which is lacking a stable 2.7.x release so far, still it limits the Python support in vert.x in an unexpected way.

It is desired being able to use botocross from vert.x verticles, so support of Python 2.5.x seems required.

• The restriction to 2.7.x has actually just been a conservative choice in absence of detailed information, so checking the Python major release notes for obvious compatibility issues might already allow to relax this.
• It's worth noting that the upstream dependency boto is supposedly compatible with Python 2.5.x still.

[sopel]

Analysis

The lists of What’s New in Python 2.6 and What’s New in Python 2.7 are rather huge and consequently difficult to comprehend in detail, but just reading though Porting to Python 2.6 and Porting to Python 2.7 seems to indicate no issues.

Conclusion

While targeting just Python 2.7 is a reasonable approach currently (Python 2.7 is planned to be the last of the 2.x releases, so we worked on making it a good release for the long term), there seem to be no specific issue preventing usage of botocross with Python 2.5 right now, so in order to ease usage with Jython the requirements are going to be relaxed accordingly.