update pylab messages

add `Populating namespace` message to `%pylab`

from @fperez
add `--matplotlib` flag to terminal IPython

just like pylab, but for `enable_matplotlib` instead
unicode fixes in SVG

minidom.parseString doesn't like unicode objects
re-run example notebooks without `%pylab`

prefer `%matplotlib` and explicit imports
update parallel example notebooks to remove `%pylab`
Rearranged htmlnotebook.txt
populate matplotlib / pylab enums from backends.keys()
removing stale files
move imports to %pylab description

from no-import-all description, which gets re-wrapped by argparse.
adding more core folks
remove quarantine

it's been long enough, and these files can always be found in the git history
Added key distinction between Notebook app and notebook documents via capitalization. Added info on different cell types and sketch of plotting
Moved htmlnotebook.txt to htmlnotebook.rst to use GitHub rendering
Moved connecting to kernel section to how to's
Clarified that 'notebook' also refers to the state of the computation inside the Notebook, but that this is the same as the content of the .ipynb file
Added input cells and basic workflow sections
Types of input cell
Magic commands section
Plotting section
Interrupting and restarting added in basic workflow