Fix destination path of #msg
craw.sh: better #wget. Fix an infinite loop with paging

This topic [1] has only 1 page. However, it contains a fragement to #blackberry
link (not sure what it is). And that will cause a very long (infinite?) loop.

[1] https://groups.google.com/forum/?_escaped_fragment_=topic/archlinuxvn/FGK-V0G3BHs

The internal fragement is

https://groups.google.com/forum/?_escaped_fragment_=topic/archlinuxvn/
  FGK-V0G3BHs#88911844-1389271758-cardhu_decombobulator_blackberry.rim.
  net-867438340-@b18.c2.bise3.blackberry_group_thread_0
README: add tips
crawler.sh: clean up #help message