In the scenario we that we have selected a commit
that is between two tags, we should base the
version on the most recent tag we can see in the
revision history, but we should not treat this as
the tag version.

`git describe --tags --abbrev=0` finds the most
recent tag visible in the revision history from
the current HEAD. Return this as the version
string and undefined as the tag to trigger ref
counting.

In the scenario that someone had cloned an entire
repository and then checked out an older version
tag, the semantic versioning would detect the
newest tag, not the checked out tag. Look for
the HEAD string prior to tag: to indicate the
currently selected tag.

In the scenario we that we have selected a commit
that is between two tags, we should base the
version on the most recent tag we can see in the
revision history, but we should not treat this as
the tag version.

`git describe --tags` finds the most recent tag
visible in the revision history from the current
HEAD. Return this as the version string and
undefined as the tag to trigger ref counting.

In the scenario that someone had cloned an entire
repository and then checked out an older version
tag, the semantic versioning would detect the
newest tag, not the checked out tag. Look for
the HEAD string prior to tag: to indicate the
currently selected tag.

Not all repositories use a v-prefix for version
tags. All tags should be considered valid
versions.

Changes parse_git url function to use Using RFC3986 standard to validate
git uri instead of matching strings in function head. Also accepts scp
style syntax for parsing.

Basic escaping is done only. Fancy hex sequences are not covered, but
this should otherwise take care of the most common issues.

Fixes #497

* fix shell commands relying on non windows shell commands
* fix shell commands using wrong quotes
* implement native wc -l