add implementation of issue #548
since try_write() is not used anywhere in the module itself, move it to the utils
Check for OSError in try_write instead of IOError
update chnagelog
Have conda clean --lock only search the places where locks could be

This makes it much faster.
Make conda config --get warn on invalid keys
Don't output a --set for an invalid key in conda config --get
Add more tests for conda config
Have run_conda_command return stderr separately
conda config: print an error message to stderr
Update tests for changed run_conda_command
Add Travis to Flowdock
Use py.test instead of nose in Travis
Travis: add debug output
Travis: use setup.py develop

Otherwise, an older Miniconda will downgrade conda when pytest is
installed. This also tests that setup.py developing works, which can't hurt.
Fix tests on Windows
select pop(0)
add new section in changelog
Update CHANGELOG
Merge branch 'master' of github.com:conda/conda

Conflicts:
	CHANGELOG.txt