Please v1.5.8

A selection of changes & fixes:

• Fix bug in go_test where it would sometimes return success if a test panicked
• plz query completions treats : as equivalent to : to help bash completion work
• go_generate rule added
• Fixes to RPC cache

Please v1.5.4

Contains minor fixes versus 1.5.4:

• Consistent naming of please_go_test
• Fix to cache_cleaner which sometimes didn't clean properly

Please v1.5.2

First stable release of the 1.5 series!

Notable / breaking changes:

• Support for build configurations, activated by '-c opt' and '-c dbg'. Those two are provided by default on C++ and Go rules; other languages can stick with a single command at present, use those and / or define their own configs. Users can define defaults in their .plzconfig.
• The 'strip' config option and go_binary argument has been removed. It's now implicit in -c opt for go_binary.
• C++ config options have changed a lot; the test / normal dichotomy has gone, we now have defaults for dbg and opt and a default set of ldflags. -lunittest++ is applied automatically by cc_test.
• --no_cache has been changed to --nocache for consistency.
• The -c argument to plz clean is now removed. Default is to clean the cache, and it honours the top-level --nocache flag if you don't want to clean that.
• python_library now has an 'out' argument where you can set the name of the output pex. It defaults to the same as before.
• More reliable returning of test output when tests time out.
• Rewritten cffi interface so startup times are significantly faster.

Please v1.4.9

First release available on the public github repo.

• plz clean now backgrounds itself when possible, in which case the user can
  continue with other tasks with no delay.
• Added licenses() builtin function for Bazel compatibility; it roughly parallels
  theirs in setting the default licence for all targets in a BUILD file. Implicitly
  we can also now use package(default_licences = [...]) which is equivalent.
• + is now allowed in names of build rules.
• Fixed .deb package to include plz_diff_graphs.