rewrite to use ledger python interface

--HG--
rename : ledgerautosync/ledger.py => ledgerautosync/ledgerwrap.py
add string_read option to use read_journal_from_string
modify mk_ledger to use python interface if available
add support for parsing ~/.ledgerrc or using LEDGER_FILE
add (c), license statements
add clean_payee function
add MANIFEST.in
bump version
exclude .pyc files
use nosetest in setup.py
setup requires mock
set test_suite for nose
better error messages when python ledger interface not found