Add blade distributed load output to AeroDyn-InflowWind C bindings

[deslaughter]

This PR is ready to be merged.

Feature or improvement description

This PR adds a flag, PointLoadOutput, to the ADI_C_PreInit subroutine in the ADI C Bindings library AeroDyn_Inflow_C_Binding.f90 which allows the user to select between point load or distributed load output at the blade mesh points. Setting this value to 0 will cause distributed loads to be output and setting it to 1 will output point loads, which is the typical output from this library.

This PR also adds the parameter HHVel_C, a 3 element float array, to ADI_C_GetRotorLoads which will contain the hub height wind velocity components (X,Y,Z), if storeHHVel was set to 1 in ADI_C_Init; otherwise, it will contain zeros. Previously, the velocities would be stored, but were not accessible through the API.

The python library, aerodyn_inflow_library.py, was updated to reflect the changes in the API.

Impacted areas of the software

AeroDyn_Inflow_C_Binding.f90 and aerodyn_inflow_library.py

Additional supporting information

Test results, if applicable

Test results were unaffected.

[andrew-platt]

Looks good! Thanks for making that change!