basic installs working

need to run tests on all the builds alone, should use a container system

tasks/helpers/cargo_build.yml

@@ -1,4 +1,15 @@
 # vim: set filetype=yaml.ansible :
+#
+## Helper: cargo_buil.yml
+## Description: download source, build and install using cargo
+## Variables: top level 'dict'
+##   source_dir: git source directory
+##   repo: git repository url
+##   depth: _int_ optional, Default 1. Git depth to clone
+##   force_git: _bool_ optional, default true. Force clone, overwriting existing dir
+##   recursive: _bool_ optional, default true. Do a recursive clone
+##   version: _string_ optional, default 'latest'. Version to checkout and build
+##   build_flags: _list[str]_ optional. If set, will append these to the build command
 ---
 - name: Cargo source install helper
   block: