Update src/blam.py

The context is now restricted on addon load, accessing the scene was don't but then never used, so simple one line correction.

See this thread:
http://markmail.org/message/5zu3bi2pnjuexyas

And this report:
http://projects.blender.org/tracker/index.php?func=detail&aid=33645&group_id=9&atid=498
Merge pull request #1 from ideasman42/patch-1

Merged in pull request from ideasman42, scene access fix.
Update README.md
added WIP html5 calibrator src
Merge branch 'master' of https://github.com/stuffmatic/blam
blam.js coordinate conversion fixes
started separating ui and calibration code
Update README.md
Update README.md
Updated wiki and issue tracker links in script header
Merge branch 'master' of https://github.com/stuffmatic/blam
Merge pull request #1 from stuffmatic/master

actual 08.13