#365 Add Turkish-locale regression test and sweep remaining bare toLo…

…werCase/toUpperCase callsites

The original PR fixed the call sites enumerated in #365 but left the
SigV4 fix unverified and three sibling callsites untouched. Add a
`Locale.ROOT` vs `tr-TR` regression test in `Aws4SignerTest` so a
revert of the canonical-header fix would be caught, fix the mirror-bug
in the test's own `buildCanonicalHeaders` (which would otherwise mask
the production bug under a Turkish JVM), and clean up `HadoopInputFile`
and `DebugParquetTest` so the repo is uniformly locale-safe.

[release]copy for tag v1.0.0.Beta2

[release] Updating release notes and CLI demo script

[release] Fixing POMs

#109 Adding API Reference link to docs

[release]copy for tag v1.0.0.Alpha1