Add cmdline flag for easy log-config

This adds a new cmdline-flag '-L', that allows to define log-levels
for single loggers by their qualname. If you instantiate the logger
via ``logging.getLogger(__name__)``, this is the modul name, e.g.:
'pyethereum.wire'.
Add console_script for eth
Add debugging hints to README
Merge pull request #50 from brainbot-com/easy_debug

Easy debug
Update eth.py

Small typo fix
Merge pull request #51 from ConceptPending/patch-1

Update eth.py
more testing scenario for trie
1. refactor test code for trie
2. add test codes for trie.delete
3. make trie.delete works, #46
finish: trie.get_size #46
remove workaround for leveldb's broken setup.py

leveldb 0.193 doesn't depend on ez_setup being installed anymore.
fix bin_to_nibbles docstring
remove trie console_script

given the fact that it didn't work at all and the limited usefulness of
pyethereum.trie as a script, remove it.

those who like to run it anyway, may type "python -m pyethereum.trie
..." instead.