Don't overescape

[elharo]

Fixes #57 To the extent the conformance tests allow, don't escape characters that don't need to be escaped. Deprecate the method that overescapes.

This should produce spec-compliant, canonically equivalent URLs. However do consider whether there's something on the server side or elsewhere that might cause signatures to no longer match. It depends on when, why, and how the signatures are calculated.

It might be worthwhile to break this PR up into smaller steps, but this is where we're heading.

@frankyn

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@4e4225f). Click here to learn what that means.
The diff coverage is 87.5%.

@@            Coverage Diff            @@
##             master      #70   +/-   ##
=========================================
  Coverage          ?   63.34%           
  Complexity        ?      531           
=========================================
  Files             ?       30           
  Lines             ?     4730           
  Branches          ?      452           
=========================================
  Hits              ?     2996           
  Misses            ?     1571           
  Partials          ?      163

Impacted Files	Coverage Δ	Complexity Δ
...n/java/com/google/cloud/storage/SignatureInfo.java	81.2% <100%> (ø)	17 <0> (?)
...ain/java/com/google/cloud/storage/StorageImpl.java	76.85% <100%> (ø)	110 <0> (?)
.../google/cloud/storage/SignedUrlEncodingHelper.java	71.42% <80%> (ø)	5 <2> (?)

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