Remove the term shearline

The shearline terminology has been replaced by lambda line and
elliptic LCS

Conflicts:
	demo/bickley_jet/hyperbolic_shear_lcs.m
	demo/bickley_jet/hyperbolic_shear_lcs_details.m
	demo/double_gyre/hyperbolic_shear_lcs.m
	demo/double_gyre/hyperbolic_shear_lcs_details.m
	demo/ocean_dataset/hyperbolic_shear_lcs.m
	demo/ocean_dataset/hyperbolic_shear_lcs_details.m