bunch of changes - see details

[esby]

metadir_py:

• alternate cache structure: by using an md5 hash of the filename of each file downloaded.
• little improvement to the old cache structure when pulling category member:
  the pagedict won't reload from disk each time a page is pulled.

clicommands.py:

• quick fix for merge command - I believe files are already in utf8 because they comes from os calls.
• rewrote throttle: a 10s delay here will mean it will take into account the request time, From my tests, it will take about 11s to commit a file. (3 api access of 3.75s). The next step will be implementing the value in metadir config.
• more verbose when committing files. date - filename - number of files left
• implemented continue for category member pulling.
• do not set api_setup again if it was already done.

If you think the code needs rework to fit needs, just ask.