add __VERSION__ attribute

[dojafoja]

Can we add a __VERSION__ attribute so my gui can grab the current running version and check for updates?

[llakssz]

sure, good idea!

[llakssz]

I just add a VERSION variable, it's that simple?

[dojafoja]

Only thing is to switch to a string to allow for versioning beyond a float value like 2.2.1. With a string I can use LooseVersion from distutils.version and make version comparisons even if you release a subversion like 2.2.1b