Merge pull request #32 from mevtho/master

Added retrieving images from the whole hierarchy when opening a folder
Added a folder hierarchy saving in the output folder
Updated French translation and fixed issue #31
Some code cleaning
Updated unix Makefile (from @ivoanjo version)
 version)

Makefile for Unix systems now use --dry-run option and includes a new
way to (un)install BIMP:
- install/uninstall for the current logged user
- admin-install/admin-uninstall for all users in the system

Uninstall procedures also remove 'bimp-locale' folder
Some updates on makefile and README
README corrections
Merge branch 'master' of https://github.com/mevtho/gimp-plugin-bimp

Conflicts:
	bin/win32/bimp.exe