Fix 'make install' target (regression introduced by 57bb526b8723ff646570287caa23b99ff9dff885)
Fix broken `opam config env` (introduced by 755124446bd0208dae6192889fc956883ad4ae55)

CAML_LIBRARY_PATH and custom compiler variables were not displayed properly.

This should fix #417
'opam config var' needs an argument

Fix #418
Add "root" to the list of implicit variables.

This should fix #419
Refactor some API bits and improve the error displayed to the user when using 'opam repository <COMMAND>s'
fix application of patches for BSD. This should fix #414
Fix stupid typo which was breaking patch application.
Small fixes to improve error recovery:

* when the extract phase is failing, recover from errors (this should fix #402)
* when the user do CTRL-C let the child clean-up properly
Do not display scarry backtrace on 'normal' exits
Fix unit-tests
Fix jenkins init
Update jenkins
cd src_ext && make distclean should work even if ./configure has not run
Really fix the jenkins init script (at least)