add some Exif tags and better format for dicts
add more timing info & version info
put tag definitions in separate module
Fixing issue #20- "global name 'Ratio' is not defined, happened after EXIF.py is split into several modules"

Import was missing.
Merge pull request #21 from peteblois/master

Fixing issue #20- "global name 'Ratio' is not defined, happened after EXIF.py is split into several modules"
centralize utils (fix ImportError)
Do not extract thumbnail in quick mode (issue #19)