Yam

* extension of images is now specified without dot, e.g. 'png', 'pdf'

* rename plotting options setting x- and y-limits to xlim and ylim
* parallel processing for stretching, reference trace must be used (--reftr)
* allow full stack with '' or 'all' (e.g. for creating a refence trace)
* parallel processing for full stack
* store correlations and sim_mat as half precission float16 by default
* fix various small bugs
* move some functions to new io module

* add scan subcommand
* add debug option (--pdb)
* add exhaustive online documentation
* add possibility to correlate "R" and "T" rotated components (experimental)
* add --parallel-inner-loop feasible for correlating many stations
* downsample now performed before preprocessing
* add decimate option (downsampling after preprocessing)
* reduce run time of tests
* fix: timenorm "clip" was not correctly working
* fix: timenorm "mute_envelope" was not working with masked data

* refactor part of the imaging module
* rename some kwargs in imaging module

* rename read_stretch to read_dicts
* remove unnecessary "root" group in HDF5 files
* change stretch to velocity change inside dictionary returned by read_stretch (sign change)
* change unit of velocity change and str_range to %
* corr_vs_time plot: allow to plot stack at top
* allow strings for length and overlap option in correlate config (e.g. "1h" for one hour)
* fix: correctly plot gaps in corr_vs_time and sim_mat plots
* fix: downsample now defaults to None (previous default: 10)

* fix: remove_response option was not working