make gemini_plot easier interface

gemini_run: clean deafults

Merge branch 'master' of https://github.com/gemini3d/mat_gemini

writegrid: auto file_format

add time parameter for plot

h5save/ncsave: check destination folder exists to avoid confusing error

matlab.cmake: correct syntax

expanduser() to avoid Matlab issues

doc

update exe check return 0