[MONDRIAN-1729][SP-632] Missed a case where the first header loaded (used for initializing the AxisInfo) contains a wildcarded column that should be downgraded to
a specific list when computing segment intersection.
MONDRIAN-1658 - handling the case where a crossjoin is given an empty set for one of its parameters.
[MONDRIAN-1729][SP-632]  Made the segments list an UnmodifiableArrayList.
Merge pull request #161 from kurtwalker/MONDRIAN-1658

MONDRIAN-1658
Merge pull request #160 from mkambol/MONDRIAN-1729

[MONDRIAN-1729][SP-632] Missed a case where the first header loaded