* The same version of obspycsv is included in ObsPy's>=1.5 io.csv module.
Therefore obspycsv will be obsolete with ObsPy>=1.5
* make reading and writing functions private
* make _events2array private, keep public version for backwards compatibility
* depth uses different header for km and m (default dep vs depm)
* removed depth_in_km kwarg in _read_csv
* allow to pass all arguments to Stream.write which are accepted by _write_csv
* use the same order of fields as in EVENTTXT files
* add read support for most EVENTTXT fields
* add load_eventtxt function to load an EVENTXT file into a numpy array
* add write support for EVENTTXT
* improve documentation