1.3.1

• Bugfix: Fixed regression with AutoToolsBuildEnvironment build helper that raised exception with not supported architectures during the calculation of the GNU triplet.
• Bugfix: Fixed pkg_config generator, previously crashing when there was no library directories in the requirements.
• Bugfix: Fixed conanfile.run() with win_bash=True quoting the paths correctly.
• Bugfix: Recovered parameter "append" to the tools.save function.
• Bugfix: Added support (documented but missing) to delete options in package_id() method using del self.info.options.<option>