Fixes #128.

In travis, use the -Werror flag, as advised by @scpeters. Doing so
required me to improve how I add the -std=c++11 flag to CMAKE_CXX_FLAGS.

In the future, the way I set CMAKE_CXX_FLAGS should maybe conform to how
@sherm1 has done it, with a separate BUILD_CXX_FLAGS variable.
Fix bug in optimizer test suite nlpqlp (for loop limit was too big). This was detected by gcc's aggressive loop optimization when it tried to unroll the loop and found itself off the end of an array. This fixes issue #128 reported by @scpeters.
Merge pull request #131 from chrisdembia/issue-128

Fixes #128

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