Makefile: make sure installdir exist, this is needed for [homebrew][]

homebrew is a package manager for mac

[homebrew]: https://github.com/mxcl/homebrew
Merge pull request #3 from godfat/installdir

Makefile: make sure installdir exist, this is needed for homebrew
Thanks!
update Changelog
Makefile: fix plist target
zh_decomp/zh_comp: fix for U+902E
zh_decomp/zh_comp: fix for U+81E7
update Changelog
dont trigger build targets again in install targets
update Changlog
update demo urls
add bsdconv_codec_check() and bsdconv_codecs_list()

todo: solve alias in bsdconv_codec_check()
make alias solving a function: bsdconv_solve_alias()
implement output mode BSDCONV_NULL
fix memory leak
solve alias in bsdconv_codec_check
don't consider it an error without ascii/{from,inter,to}_alias installed
return solved codec name in bsdconv_codec_check()
rename bsdconv_codec_check() to bsdconv_codec_lookup()
exclude found codecs whose filename has '.' (".", "..", and callback libraries)
1) allowing using operators in aliases
2) revert bsdconv_codec_lookup() back to bsdconv_codec_check()
3) add bsdconv_pack()