chore: remove outdated files

Author: mchitre

src/UnderwaterAcoustics.jl

@@ -1,13 +1,14 @@
 module UnderwaterAcoustics
 
+# common utilities
 include("utils.jl")
+
+# underwater acoustics
 include("uw_basic.jl")
+
+# propagation modeling
 include("pm_api.jl")
 include("pm_stdlib.jl")
 include("pm_pekeris.jl")
 
-# include("pm_core.jl")
-# include("pm_basic.jl")
-# include("pm_all.jl")
-
 end # module