Each uri component needs to be uri-encoded.
Path components cannot be escaped with QueryEscape.
Add few test-cases from aws4 test suite for path encoding.
Merge pull request #19 from pxi/canonical-uri-fix

Each uri component needs to be uri-encoded.
Missing region name for S3.
Add parentheses test.
Fix URI encoding by encoding all chars not found from the exclude set.
Merge branch 'master' into canonical-uri-fix