fomosto export: use a better default name when user specifies directory
cake: use potential interpolation selectively for P and S

fixes a problem when there is a gradient in either P or S
trace.correlate: fixed a problem with newer scipy versions
parimap: prevent a hang in Process.join()
snuffler: can now specify stream selectors in raw slinktool format

If there is an underscore in the selector part of the seedlink url,
all stream selectors are passed to slinktool's -S option as they are.
No info query is done in this case.
sac: fixed incorrect handling of null-terminated header values
added conversion methods between mopad's and pyrocko's mt
fomosto view --show-phases adds phase markers
fixed bug in fomostos view with phases option
fomosto view with markers accepts a list of phase ids, or all
fomosto modelview: new option creates model plots
fixed a bug in fomosto modelview
Merge pull request #28 from HerrMuellerluedenscheid/uplink

new features in fomosto and a convenience method in mopad
gf store: added C implementation of Store.sum()
store_ext.c: improved error handling
moment_tensor: magnitude and moment args for random_dc()
misfit setups: changed guts-type of domain to StringChoice
seismosizer engine: cache discretized source models
Store.t(): allow source/targets as input arguments
guts: allow for tuple with arbitrary length