[TEST] some xmla tests were still failing for jdbcUrl with ampersands
[MONDRIAN-1028] vertica dialect fixes

from evergreen
- e69470d60916e0588955f4a5d8d5947aa15d6f18 Fixed issues found while
running Vertica test suite. SegmentLoader has issues with Null Doubles,
and the Vertica Dialect doesn't handle Longs well.
- also minor dialect changes
d5ed2859e10ed623575997f5d2e3f9bcbce10f27
1db658ec395198608ebb02648f730ab32781ad6c
[MONDRIAN-1028] SegmentLoader has issues with Null Doubles

from evergreen:
- e69470d60916e0588955f4a5d8d5947aa15d6f18 Fixed issues found while
running Vertica test suite. SegmentLoader has issues with Null Doubles,
and the Vertica Dialect doesn't handle Longs well.
[MONDRIAN-1028] getting more tests passing against vertica, these were all
test suite adjustments.

fixes DialectTest messages and tests failing from sum(null)
[MONDRIAN-1028] fix xmla type mismatches for vertica
[MONDRIAN-1028] DialectTest.testBigInt was failing with aggregates enabled

due to no measures from fact table
Merge pull request #409 from tgf/verticaTests

[MONDRIAN-1028] Vertica tests