#38 Install config and palettes to a subdir of $(DESTDIR)

[Sergei Golovan]

Hi!

Currently (BLT 3.0 from the Git's HEAD), make install installs everything into subdirectories of $(DESTDIR), which is good, but in the code which installs bltConfig.sh and palettes $(DESTDIR) is missing, so they go under the system root.

The attached patch adds $(DESTDIR) to the relevant install targets. It also adds a loop over the subdirectories for the destclean target which might be useful also.