Cover connection errors (ns_connect and ns_bind)
Squashed 'deps/frozen/' content from commit e6e1014

git-subtree-dir: deps/frozen
git-subtree-split: e6e101453d4cc2bff199b3402dc30c1cbed08175
Merge commit '4ed59c9a4cdfd1fe84f690c3758512b966eb6a19' as 'deps/frozen'
Use `frozen` module bundled in the substree
Merge pull request #129 from cesanta/test_conn_create_errors

Cover connection errors (ns_connect and ns_bind)
Merge pull request #130 from cesanta/subtree

Bundle `frozen` dependency (and possibly others) with git subtree
Add local git hooks and an install target

Core developers and frequent contributors can install the hooks by running:

  make setup-hooks

The hooks will:

 - ensure that the sources are amalgamated when committing

 - that the commit message follows the GitHub guidelines

 - append the GitHub guidelines to the commit message template

If the commit message check fails, it will show the user how to
re-edit the previous commit message.

The hooks are implemented as shell scripts.