updates point location routines; updates station duplets search (by hash table) #179

Job	Run time
Check file changes	20s
Test on Mac	11m 30s
Test on ubuntu-latest	2m 4s
Test on ubuntu-20.04	2m 24s
Test Intel on ubuntu-20.04	6m 2s
Test run example 3 - layered halfspace	3m 20s
Test run example 0 - make tests	7m 32s
Test run example 2 - fault tpv5	5m 24s
Test run example 1 - meshfem3D simple model	4m 28s
Test run example 4 - small adjoint	3m 42s
Test run example 5 - socal1D	4m 2s
Test run example 6 - socal1D 1d_socal	3m 12s
Test run example 10 - homogeneous halfspace	3m 1s
Test run example 11 - poroelastic	4m 1s
Test run example 13 - PML acoustic	2m 17s
Test run example 14 - waterlayered halfspace	3m 38s
Test run example 12 - PML elastic	2m 36s
Test run example 7 - socal1D 1d_prem	3m 30s
Test run example 8 - socal1D 1d_cascadia	3m 46s
Test run example 9 - coupling FK	3m 29s
Test run example 15 - tomographic model	3m 4s
Test run example 16 - cavity	2m 36s
Test run example 17 - sep bathymetry	3m 27s
Test run example 18 - socal1D hdf5 i/o	3m 34s
	1h 32m 59s

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