Tagging Ganga version 6.1.15

Tagging Ganga version 6.1.14

Tagging release scripts for 6.1.14

Tagging Ganga version 6.1.13

Updating to require LHCBDIRAC_v8r1p12

Tagging Ganga version 6.1.12

Tagging Ganga version 6.1.11

Tagging Ganga version 6.1.10

Updating install script removing PYTF

Updating deps to drop lots of unused externals, updating lhcb-prepare…

… to current best state