Split the trim function inputCovering() and update the output type
Add a test that demonstrates the problem.
Cannot remove group loop initial table if it's the only one, even if columns unused. Its rows determine cardinality.

Fixes #1315
merge MMcM: Cannot remove group loop target table if it's the only table in group

Merge pull request #1316 from MMcM/sql-layer/sql-group-loop-single-unreferenced-table
https://github.com/FoundationDB/sql-layer/pull/1316
Address the TRegex (REGEX) function input parameters.
TLike to get values correctly.
Tweak TRegex for input values.
Serial sequence -> Leave the covering on all the varchar columns, update
the output type.
Sequence NEXT|CUR VAL -> leave the covering. Add test to verify.
Fix QuoteIdent, with test
Remove dead code from Trim
Inputs to L|R PAD function
Fix Locate/Position, update test.
Add test for Coalesce, but leave it alone.
Add test for CONCAT, verifies it works as expected.
Add tests for replace, strcmp. No changes to the code recommended.
Fix Substring_index, with tests.
Release 1.9.5
Bump version to 1.9.6
Last set of reviews. Tweak QuoteIdent, Trim to get nulls correct. 
Add more tests for other potentally affected, but not updated,
functions.
More test tweaks to resolve problems when the code changes propigate.
Fix the pom.xml

Address merge comments - Fix length of QuoteIdent, SerialSequence.
Extract method from Trim to commnon ancestor.