fix calling with conda with --prefix option
Add conda_api.search
Add remove, remove_environment, package_info
Add config_get, config_set, etc.
Add conda update
Add conda launch
Make CondaEnvExistsError inherit from CondaError
Support conda search --spec
Rename launch() to run()
Fix get_conda_version in Python 3.4
Add basic tests
Update --path to --prefix
Make API more consistent