Modified default sample size in query.trait.data functions

take.samples() had different default (10^6) than derive.trait()
and derive.traits() (10000). In addition, only the former was ever used.
Cleaned up to avoid future confusion.
Initial commit to address gh-245

Passed build.sh --install --test and my own tests.
Could close gh-245 but please double-check.
Merge branch 'master' of github.com:PecanProject/pecan into gh245_fix
Merge pull request #261 from ryankelly-uiuc/gh245_fix

Gh245 fix