Configure Travis to work with scipy installation

[eywalker]

Introduction of scipy as part of requirements required a number of changes to Travis configuration, including:

• explicit installation of dependencies: BLAS, LAPACK, ATLAS, and Fortran
• extension of Travis time delay to cope with long build time for scipy. Travis times out after 10 min of non-response and this was preventing successful build under Python 3.5. Extended this to 30 min.

These modifications allow for scipy to be built and the rest of the test to be run. However, building of scipy alone extends the test time by nearly 10min, and we might want to look into other methods to speed up the test run time.

[coveralls]

Coverage remained the same at 75.575% when pulling bbb9269 on eywalker:master into e1e086b on datajoint:master.