Minor edit to makezip bat to work with latest version of buildenv.
Merge pull request #158 from Ghostwalker71/fix/install_bat

Minor edit to makezip bat to work with latest version of buildenv.
Texture state flags use bools.
Refactored texture slot generation.
Simplified texture access
Removed try catchs from apply_mode access.
Updated texture_effect to use import_image_texture()
Fixed a few misnamed variables, Reset None for texture flags, must be
none not false.
used hasattr instead of try for setting tau and damping.
Added return b_mat_textslot to store texture types.
Slight change to shader import to remove specific shader type
dependency.