Update leinigen to 2.5.1. The .jar file is now a .zip file but they
are the same thing, so we just install it as a .jar file.
Changelog:
No longer skip certificate checking when upgrading on Windows. (Phil
Hagelberg)
Fix password prompt for Cygwin users. (Carsten Behring)
Fix a bug where lein pom did not add the project's SCM URL to
pom.xml. (Fredrick Giasson)
lein clean now cleans up all profile targets. (Jeb Beich, Jim
Crossley)
The order included profiles are merged in is now retained. (Jim
Crossley)
Fix a bug preventing update-in to use functions not yet
required. (Phil Hagelberg)
Allow multiple :repl profiles. (Hugo Duncan)
Fix an infinite recursion bug with aliases and with-profile. (Hugo
Duncan)
Add flexibility in jar manifest declarations. (Fabio Tudone)
Fix a bug preventing extra profiles from being included in jars. (Hugo
Duncan)
Fix a bug in self-install on Windows. (Sindunata Sudarmaji)