Add missing dependency

This package requires py-lxml.
Add gmake to USE_TOOLS

GNU make is a dependency of the build process.
Add packages/ to .gitignore

packages/ contain built packages ready to install, don't track them.
Merge remote-tracking branch 'origin/hgview'
Merge remote-tracking branch 'origin/terminator'
Merge remote-tracking branch 'origin/xentools42'
Enhance packaging terminator: add py- prefix, include desktop-file-utils/desktopdb.mk, rename repository to py-terminator