ocp-build: install and uninstall packages

ocp-build -install: install compiled packages
ocp-build -reverse-install: reverse the installation of compiled packages
ocp-build -uninstall: uninstall packages by name

options:
-install-lib: where to install library files (each package is put in a
   different directory, by its name)
-install-bin: where to install binary files (/usr/bin for example)
-install-data: where to install data files (/usr/share for example)

META files are generated, and should allow to link to libraries
Merge branch 'typerex2' of github.com:OCamlPro/typerex into typerex2

Conflicts:
	Makefile
ocp-build: META loading tested