5.7.9beta48

Mbmosaic: Fixed parsing of the -Ypriority_source option when priority_source is
a filename.

Mbm_grdplot: Fixed handling of image file min max when color_mode == 6.

Mbnavadjust: Added controls allowing the mode of global ties to be changed
interactively.

Mbnavadjust: Changed project file format, adding the the id of the source
reference grid used for each global tie.

Mbview library: Fixed problem where mbview did not render the last row and
column of a grid (the easternmost and northernmost data). Also attempted to
make picking more robust.

Mbnavadjust: Fixed interpolation of global ties to create the starting navigation
model during inversions. Fixed several actions in section and reference grid mode.