Yamlpath

Bug Fixes:
* eyaml-rotate-keys was broken by the refactoring for 2.0.0. eyaml-rotate-keys
v1.0.2 restores functionality.

Enhancements:
* Command-line tools are now managed via pip as entry_points/console_scripts
rather than external binaries. This enables superior cross-platform
compatibility as well as unit testing. As such, all of the CLI tools have
been updated pursuant to (generally trivial, excepting eyaml-rotate-keys)
issues discovered during their newfound CI tests.

Bug Fixes:
* yaml-set v1.0.4 lost track of EYAML block formatting between read and write,
causing replacement values to use unexpected formatting. This is fixed in
yaml-set v.1.0.5.

Enhancements:
* Added Collectors to YAML Path expressions. These take the form of "(YAML
Path)" -- parenthesis () are used to demarcate each Collector -- resulting in
a list of zero or more matches for the sub-query. Operators between
Collectors include + and -, like "(...)+(...)", "(...)-(...)", and nested
Collectors are possible, like "(...)-((...)+(...))". Collectors may appear
anywhere within the outer YAML Path, effectively setting the point within the
data at which each Collector is rooted.
* A major code refactoring was undertaken to break YAMLPath out as its own class
and improve code quality (per mypy and pylint).

Bug Fixes:
* yaml-set v1.0.4 now implies --mustexist when --saveto is set. Otherwise,
--saveto was trying to save nothing when --change (without --mustexist)
pointed nowhere.

Bug Fixes:
* yaml-set v1.0.3 no longer requires --privatekey unless decryption is requested
via enabling --check. As a side-effect, the script will also no longer ignore
requests to set the same value as was already set.

Bug Fixes:
* yaml-set v1.0.2 now preserves newlines for pre-folded EYAML values when saving
the old encrypted value to another node.
* ruamel.yaml v0.15.96 is now the minimum acceptable version in order to adopt
better round-trip editing.

Enhancements:
* Set minimum compatible versions of Python and ruamel.yaml in order to ensure
users experience the expected behaviors.